text:
Software to do Duplo train track layout?
Anyone know a way to create with a software DUPLO train track layout?
The only thing I found is:
http://www.anyrail.com/index_en.html
It's a bit overkill for what I need and it's $US60, although the limited version can be used free.
LEGO has a track planner for non DUPLO track.
http://www.lego.com/en-us/city/trains/track-planner
If I can't find something, I'll probably try to do it myself (I have a background of tools programmer in video game industry)

I've used a program called WinRail that again is probably overkill for what you need, but was great for me with Brio, HO/OO and Scalextric. I know it has some LEGO elements in it, I'll check tonight if it has DUPLO as well...

Rather belated response - No, my WinRail10 instance only had LEGO Trains and LEGO 9V Trains, but I think the points were off in both of those - at least, they don't match the points I've floating around somewhere.

I asked question on here about Lego System track layout, I've 1st type blue rails. The points like 2× straight with 1 end having 2 track side by side. Later = points like part of circle with straight tangent. So need to know what Duplo points are like, then 1 of System track software should do.

See has both parallel & curved out points, 2 sizes track length, like more advance than System rails?

I would recommend BlueBrick, which is a versatile LEGO layout editor by Alban Nanty.
Apperently it has Duplo parts too, so I believe it should meet your needs. It can actually do much more for your layout planning needs (including modular tables if your club has some, for example), so maybe you'll consider it overkill as well, but since it's specifically made for LEGO layout I think you should be hapy with it.
Disclaimer: I have never used it for Duplo myself - if you do, feel free to share your experience with us in a comment.

BlueBrick work!  It's not perfect, but it's free and open source which is really great!  Thansk a lot!

You can use RailModeller Express or RailModeller Pro on macOS.
Both feature LEGO tracks (regular and Duplo):
http://www.railmodeller.com/libraries.html

..the Express edition being completely free to use :-)

Thanks for mentioning our macOS apps!
You can also use our free app RailModeller Express for LEGO Duplo trains: http://www.railmodeller.com/express-edition-en.html
For iPads please check our new iOS app:
https://itunes.apple.com/us/app/play-well-d-train/id1231936324?mt=8&at=1000lp7a

mayTracks - Lego Duplo Track Creator
A bit late - but there is an app for Windows and/or MAC to create DUPLO tracks with most known DUPLO bricks. I tested it and it works nice. In minutes and with a view clicks - I created large track plans. There is a PDF export too.
https://maytracks.maydorf.com


text:
Fixing poorly applied stickers
Does anyone have any tricks to removing a sticker and reapplying, after a significant period of time?  I recently purchased a lot of sets from 2000-2010 range, and the stickers look like they were applied by my 4-year old, while blindfolded...
I'm dealing with sets like Town Plan, and Joker's Ice Cream Surprise, so purchasing new stickers is not an option, and unfortunately stickers really make the sets in these two instances.  I'm hoping someone has experience with using a glue or something else to repair the adhesion.

Yeah, new stickers are not an option.  At the time of this posting, there is 1 lot on BL for Joker's Ice Cream at $200.  Frustrating...

Unfortunately older stickers are difficult to remove and reapply because the sticky part of the paper tend to rip off and leave a residue on the LEGO element itself. But the fact of the matter is that applying that taking off and re-applying even a new sticker is a challenge and it will almost always be visibly damaged at least a little bit.
Your best bet is just to get new stickers. You can find pretty much any sticker-sheet LEGO ever released all the way back from the beginning, and many times in new condition. In fact several Bricklink stores specialize in selling old stickers.
Just go to Bricklink, type in the set number and look at the inventory listing. The sticker sheet will be included there. Then see which seller have it at what prices and choose the one you like the most.
Here is the general listing of all LEGO stickers: http://www.bricklink.com/catalogList.asp?catType=P&catString=160

To remove stickers, I use lighter fluid.  However, it can damage plastics, and I've never used it on LEGO bricks before, so please test it first.
Apply the lighter fluid to the sticker, and use a sharp metal object (like an X-Acto Knife) to slowly pry the sticker from the brick.  You will probably have to regularly apply the lighter fluid as new parts of the sticker are exposed.
Once removed, set the sticker grahpics-side down a piece of newspaper or other disposable surface.  To restore the stickiness, spray the back side with spray glue or spray adhesive, available in most craft stores.  Now, immediately reapply to your bricks.
CAUTION:  chemicals like lighter fluid, Goo Gone, spray adhesive, etc. can damage both the stickers and the plastic bricks.  Test this process with an unimportant brick first.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/

sort: votes


text:
Where do bulk LEGO sellers on eBay get their bricks?
The are a large number of people on ebay selling LEGO by the pound(or kg), for example, this guy. The LEGO is (implied to be) pre-owned as the eBay descriptions often say the bricks have been washed and sorted and non-LEGO brand bricks removed. These seller sometimes have 10's or maybe 100's of pounds of LEGO for sale.
Where do they get all this LEGO? And how much do they pay for it?

+1 I had the exact same question in mind when I saw a person selling pounds of Lego bricks. His answer is similar to the answer below, and he also mentioned that he gets a lot from his family and friends, as they know that he does this stuff.

Garage-sales, estate-sales, second-hand stores, flea-markets and graigslists are the most common way to source out used LEGO. This is especially true in neighborhoods where there is a LEGO store nearby so a lot of kids have them, or where LEGO is popular in the community in general (suburbs and middle-class neighborhoods are especially great places to scout).
As far as how much they pay for it, it just depends on the deal, but of course the less is better. These buyers often make an offer on an entire lot to get the best deal, and they are very familiar with what sells the best and for how much.
They wash them, clean them, then cherry-pick the minifigs and expensive parts out they will sell separately on eBay or BrickLink and dump the rest on eBay as mixed lots. It is not easy work by any means, but it can be a lucrative business.

Great answer +1. I could not understand how it can be a lucrative business. Anyone who owns Lego, knows its worth very well. In addition, buying it from others and then selling it, wouldn't that make the profit margin less? I do agree that it is not an easy task.

@Farhan - It isn't necessarily true that people who own LEGO know how much it is worth. Maybe they do, maybe they don't. Just depends on who they are and how they aquired it. Also, just like with everything else, it is not always about the money. Some people just want to clean house and get rid of stuff and they don't have the time to research what they have or sell it in the most ideal way. They are happy if you help them get rid of it all. I was reading a post on reddit about someone finding an almost new LEGO set in the dumpster!

I asked a similar question about finding older sets and I got a good list of places to check out. This might be useful for your searches. Good hunting!

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
Guide me on how to use my Mindstorm RCX kit on OS X Mavericks
Any suggestions on how I can use my old RCX set on Mavericks? I have set up Xcode command line tools, and I am getting compiler errors while trying to download nqc through Macports. Even downloading gcc49 through Homebrew has not helped fix this issue. Is there any other option I'm overlooking?

I struggled with backwards-compatibility with NQC myself. A couple months ago I made the switch to leJOS, so far its been great.

Thanks for your response Keshav. I'd ideally like to stick with NQC but even leJOS is giving me issues. Despite setting up the PATH variables correctly, I keep getting "clang: error: no input files" errors when running Ant. Fiddling around with the main build.xml and build.properties files also does not seem to work

I am currently maintaining my own fork of NQC for use on OpenBSD and OS X. As you have discovered, the recent compiler changes on OS X broke NQC in many places. Not to mention that the USB tower integration was pretty outdated. If you can compile it, it should work better than the ports version.
AFAIK, I am now the de facto maintainer for  NQC. (And may Crom have mercy on my soul, etc.)
Also, If you can find the right firmware (available around the usual places) you can update the RCX 1.0 to something like 2.x (or whatever the last release of the RCX firmware from LEGO is).
I make no promises this works at all, but I recall the last checked in version worked reasonably well with a serial tower on OpenBSD and a USB tower on OS X. A serial tower on OS X might work with the right incantations and USB/serial dongle.
If someone else other than me actually uses this, I might be prompted to cleanup my sandbox and commit my local repo (and fix bugs others find annoying.)


text:
Is the NXT forward compatible with EV3 sensors and motors?
Is it possible to use EV3 sensors and motors with the NXT intelligent brick? I've read that the EV3 is backward compatible with NXT motors and sensors, but does vice versa work as well? Is the NXT forward compatible with EV3 sensors and motors?

5 months late but... I would argue that this is not a duplicate since the question linked to asks about the EV3 being backward compatible with NXT sensors and motors, whereas this question is vice versa; it asks about the NXT having forward compatibility with the EV3 sensors and motors, which is addressed in neither the linked question nor its answers. I went ahead and edited the question to be more clear, as well as nominated this for re-opening.

Short answer: you can use EV3 motors with NXT, but you can't use EV3 sensors on NXT. NXT sensors and motors work with EV3.
Detailed answer: read Laurens Valk paper.

The NXT works fine with EV3 motors, and will read them as NXT motors. EV3 sensors, on the other hand, do not natively work with the NXT, with the exception of the touch sensor.
The reason for this is that, touch sensor notwithstanding, EV3 sensors use a hardware communication protocol called UART, which is not supported by the NXT. The NXT only supports analog and digital I2C. The EV3 touch sensor works with the NXT because it's an analog sensor, unlike the other EV3 sensors.
That being said, it is possible to make EV3 sensors work with the NXT via an EV3 sensor adapter:

An adapter is required for each sensor port used. Unfortunately, it's not currently supported in NXT-G; just in NXC and EV3-G.


text:
How well do LEGO assemblies hold water?
Water is commonly represented with blue pieces, but what if I tried adding real water to a setup?
For example, I create a simple blue base with a rectangle making a sort of pool. If I fill that rectangle, would the water be held inside the pool?

Example 2, make a river using taller pieces as the bank and run water over it.

I already saw that LEGO bricks can float so maybe adding a nifty crocodile into a moat or something.

In my experience, this doesn't work very well. The gaps between LEGO bricks are too wide to hold water. The water will be contained for a short amount of time, but it will eventually leak out through the cracks.
Here's an experiment showing how your first example works. Notice the water leaking out the crack in the bottom right:

The leak continues to grow:

I haven't personally tested this with running water, but I can only imagine that this would increase the rate that water will leak out.
If you're interested in building some sort of running water feature, you may want to take a look at this answer that suggests waterproofing the bricks using liquid latex after assembly.

You will have less leakage with a double wall of 1xN bricks, but IME it still leaks (I've built boats rather than ponds, but the result is the same)

What if you used those really short ones in a brick-layer formation (half on one block, half on the next)?  Shouldn't that remove the bigger holes?

lego water has to be blue. yours is boringly transparent. +1 for science

I did something like this once, I cut down a butter tub and built the lego around it, with plates hiding the top edge.  It worked very well, but the stale tea that I used for the swamp stained my bricks.
I can only think that a brick-built wall with a plastic carrier bag secured by a plate layer at the very top would be your best bet, as none of the bricks would be modified, and the shape can be completely random.
And as you can see, both crocodiles and sharks float nicely.

Cunning plan there Windfire, that should work nicely. An alternative to the carrier bag would be clingfilm/film wrap.


text:
"The type or namespace name "Brick" could not be found" Xamarin Studio with MonoBrick
I managed to establish a wifi connection with the Ev3 Brick via WinSCD and am programming the Ev3 with XamarinStudio/Mono Develop(http://xamarin.com/studio "XamarinStudio"). My problem is that "The type or namespace name 'Brick' could not be found (are you missing a using directive or an assembly reference?)"
The Code is:
var ev3 = new Brick <TouchSensor, IRSensor, ColorSensor, ColorSensor>("wifi");

as you can see at the screenshot below...

What are your Project References ?

The References are only the MonoBrickFirmware.dll

You need to be using the standard MonoBrick Communication Library if you want to connect remotely to the EV3.
You would then need to have the following using statement at the top of your code:
using MonoBrick.Ev3

I believe you are referencing the MonoBrick EV3 Firmware which doesn't need to connect to the brick as it is the brick.


text:
What happened to Cuusoo set #6
Lego Cuusoo just announced set #7 Ghostbusters 30th anniversary.  Cuusoo set #5 is the Curiousity Rover.
Why is there no set #6?  What happened to it or did Lego announce it and then change their minds?

Looks like LEGO switched up the numbering of the CUUSOO/Lego Idea sets.  The Ghostbusters set is officially #006 as can be see on the Lego.com site and now that review units of the Exo-Suit have been released to several Lego related blog sites, it has the number #007 on it.
Official LEGO Shop listing of Ghostbusters set Click on the box image
Review of Exo Suit
Hi Res shot of Exo Suit box

Time lapse of Tommy Williamson (BrickNerd) building the ExoSuit. So looking forward to August 1.

The sixth LEGO CUUSOO set is the upcoming Exo Suit. See announcement here: http://blog.lego.cuusoo.com/2013/10/21/results-of-winter-spring-summer-lego-reviews/


text:
Is there an .lxf file resource of production Lego sets?
Is there an .lxf file resource site of production Lego sets? Specifically, I am looking for the Millennium Falcon 10179 lxf file, to load into Lego Digital Designer.

The Eurobricks forum has a topic dedicated to user created LDD files of existing LEGO sets.
There are currently four different versions of the #10179 Millennium Falcon made by different users:

yellost (23 August 2010)
bbqqq (12 November 2010)
Calabar (20 October 2012)
kcoon (16 December 2013)

There is also a topic for official LEGO sets re-created in ldraw.

There's also an article on the LDraw site on how files represeting official models should be created which hints at a repository, but doesn't link to it...


text:
Why are minifigure wrenches tapered at the end?
The common minifigure wrench is tapered at one end.  Why?  None of the other minifigure tools are shaped this way.  Is the wrench meant to also serve as a minifigure pry bar?  Or perhaps as some sort of flathead screwdriver?

The wrench is also supplied (usually in red) in the LEGO Games sets as a handy way to remove the faces (2x2 tiles) from the die.

@Zhaph-BenDuguid The ones supplied in games were also black. They were indeed later replaced by a red part, but a different one: the crowbar, which has a similar tapered end. In general, both do help remove tiles from just everywhere, but I wonder if that was the intend when the part was created for 1979 sets.

@Joubarc Good point, you're right it's a red crowbar now.

Your second guess was correct. It's not just a wrench. It's listed as a Screwdriver/spanner on Lego.com:

This part was also included in several sets in the Games line as a human tool to remove tiles from the dice. It's unclear (at least to me) whether this part was intended to be used for tile removal when it was introduced in 1979. Here's an example from the Creationary instructions:

Okay, but that raises more questions: Is it supposed to represent a screwdriver for minifigures' "use" (in which case it's even more disproportionately large) or for humans (in which case, to drive what screws)?

It's intended as a screwdriver for minifigs. As a human tool, it has been included in the Games line for removing tiles from dice. I'm not aware of any instance where this was intended as a usable screwdriver.

I think what feels a bit unsatisfying is that it seems bizarre as a screwdriver.  While I normally have a suspension of disbelief when it comes to the proportions of minifigures and their handheld tools, it doesn't work for me here since in the real world, screwdrivers are not normally the size of wrenches.  It's odd that they chose to create a combination that, AFAIK, does not commonly exist.  If they wanted minifigures to have a screwdriver tool, a separate piece would have been much better.

I agree. This seems to be a particularly strange decision considering that there is a separate screwdriver tool for minifigs (although it didn't appear until 1995). http://peeron.com/inv/parts/6246a


text:
LEGO Power Functions M-Motor 8883 characteristics
I have a couple questions about LEGO Power Functions M-Motor 8883 (http://shop.lego.com/en-US/LEGO-Power-Functions-M-Motor-8883):

Is it synchronous or asynchronous?
It is powered by AC or DC?

Find useful article about motors: http://www.philohome.com/motors/motorcomp.htm but there are no answers on my questions.

The basic LEGO Power Functions motors (M, L, XL) use a fairly standard DC motor internally. The terms synchronous and asynchronous only apply to AC motors.
I'm not sure exactly where you are headed with this question, but if you are curious about whether or not PF motors can be controlled directly from a simple voltage source, the answer is yes. You don't need any complex control circuitry for the basic motors. Power is fed directly from the PF control lines (the middle two wires) to a DC motor.
The following image shows the internals of the PF XL motor. It is electrically identical to the M motor. You can see that it has no control circuitry, and connects the control lines directly to the terminals of a basic DC motor. The only additional components are a couple of capacitors to help eliminate signal noise.

More detailed information on the PF system can be found here:
http://www.philohome.com/pf/pf.htm


text:
How do I get instructions to fully motorize Technic 42006
I have just purchased the Technic 42006 and would like to make it fully remote controlled.

Is that beyond the instructions listed from pages 34 onwards in book 2?

I suggest using google to search for them.
When I did that I found two threads on EuroBricks discussing this - here and here. The first thread links to a youtube video that has downloadable instructions. Note that the instructions are 19MB and the website is fairly slow.


text:
EV3 Event Delegation
My problem is that the robot, which should just remain in the program until the Escape Button is pressed, just stays in the while-loop. The current code looks like this:
using System;
using MonoBrickFirmware;
using MonoBrickFirmware.Movement;
using MonoBrickFirmware.Display;
using MonoBrickFirmware.Sensors;
using MonoBrickFirmware.UserInput;
using System.Threading;

namespace ColorSensorExample
{
    class R_Main
    {
        public static void Main (string[] args)
        {
            R_Main main = new R_Main ();
        }

        public R_Main()
        {

            var sensor = new EV3ColorSensor (SensorPort.In2);
            ButtonEvents buts = new ButtonEvents ();
            buts.EscapePressed += new Action(onEscape);
            while (true)
            {

            }
        }

        private void onEscape()
        {
            EventWaitHandle stopped = new ManualResetEvent (false);
            stopped.Set ();
        }
    }
}

But it does work with the example from the Monobrick homepage:
using System;
using MonoBrickFirmware;
using MonoBrickFirmware.Movement;
using MonoBrickFirmware.Display;
using MonoBrickFirmware.Sensors;
using MonoBrickFirmware.UserInput;
using System.Threading;
namespace ColorSensorExample
{
class MainClass
{
  public static void Main (string[] args)
  {
        EventWaitHandle stopped = new ManualResetEvent(false);
        ColorMode[] modes = {ColorMode.Color, ColorMode.Reflection,
                             ColorMode.Ambient, ColorMode.Blue};
        int modeIdx = 0;
        var sensor = new ColorSensor(SensorPort.In1);
        ButtonEvents buts = new ButtonEvents ();

        buts.EscapePressed += () => {
            stopped.Set();
        };
        buts.UpPressed += () => {
            LcdConsole.WriteLine("Sensor value: " + sensor.ReadAsString());
        };
        buts.DownPressed += () => {
            LcdConsole.WriteLine("Raw sensor value: " + sensor.ReadRaw());
        };
        buts.EnterPressed += () => {
            modeIdx = (modeIdx+1)%modes.Length;
            sensor.Mode = modes[modeIdx];
            LcdConsole.WriteLine("Sensor mode is: " + modes[modeIdx]);
        };
        stopped.WaitOne();
    }
  }
}

Note: I have no particular knowledge of how monobrick work.

You're never escaping the while (true) loop. The example you're pointing too use an event-based model, and it looks like you prefer a loop. This is what you want:
class R_Main
{
    public static void Main (string[] args)
    {
        R_Main main = new R_Main ();
    }

    public R_Main()
    {

        var sensor = new EV3ColorSensor (SensorPort.In2);
        bool continue = true;
        ButtonEvents buts = new ButtonEvents ();
        buts.EscapePressed += () => {continue = false;};
        while (continue)
        {

        }
    }
}

But depending on the internals of monobrick this might not work at all.


text:
NXT program not running
We have multiple NXT Bricks. We can read sensor data and motor degrees from View. Some are running FW 1.31, others FW 1.28.
When we try a simple 5-step NXT program, the motors will not turn. We tries wait blocks after the move blocks. This only occurs on some of the bricks, and there is no correlation with the FW version.

Did you use in program the same motors as you check via View? For example, maybe you view A and B motors, but in program uses C and D?
If you have the following behaviour:

You check motors via View, then create a program and it works. After
  that you substitute NXT brick for another one, check the same motors
  via View but that same program doesn't work.

In that case I'd suggest to refresh firmware.

We made sure to use the correct motor ports when checking view and running the program. We will try refreshing the firmware.


text:
Logging and performing mathmatical calc. during run?
Is it possible using the new EV3 to log data, and peform mathmatical calculation on the data while it's being logged, and peform some and thereby trigger some event if some value has been reached??
As far i can see, it is possible doing seperatly..

Instead of using the datalog block from education version, you can create a custom version using the file access block. It's a bit more difficult, but more flexible...
You won't be able to directly use EV3 datalog management, but you can structure the file to be directly compatible with csv format, readable by spreadsheet programs.

As @Philo mentioned, the EV3's native datalog block is very limited. Instead, you can use the File Access block and then export it to your computer.
CSV Format is as follows:
Year,Make,Model,Length
1997,Ford,E350,2.34
2000,Mercury,Cougar,2.38


text:
How make a 6x6 board rotate using LEGO technic parts?
Are there any common patterns for making a 6x6 (or bigger) LEGO board have a ability to rotate using technic with gears and such? Has to be without the help of the existing 2x2 lego part that rotates, its not big enough.
Seen from above:

Would you like the 6x6 plate to rotate on some kind of axis, or would it suffice to have some kind of coaster system that you rotate by holding the 6x6 plate and turning it yourself?

A simple, brutal solution if you want motorisation would be a round plate that has an axle hole, attached to an axle attached to the motor.

You can use a large gear (3649) with connector pegs (970607) attached like this:

Then you can attach the 6x6 plate on top.

For smaller assemblies, a 2x2 round brick is probably more than you'll ever need as it has a cross hole in the middle

@Joubarc: I was thinking of that too, but the OP said that "existing 2x2 lego part is not big enough", so I didn't suggest that.

I thought he meant the turntable, but you're probably right

There's actually a specialized part to accomplish this task. Take a look at the Technic Turntable (2855):

This part can be used to create sturdy rotating platforms that can be controlled by gears. It consists of two parts (2855 and 2856) that snap together to allow for smooth rotation about the center. Here's an example from the classic Mobile Crane set:

With the crane boom mounted:

Note that this turntable is out of production, so it may be easier to find the new studless version, though it will obviously be a little more difficult to attach regular bricks to this one. The studless version is part 48452 and 48168. Here's what is looks like with the two halves snapped together:

There are several different turntables, the one linked is somewhat old and might be hard to find. Bricklink has a category list: http://www.bricklink.com/catalogList.asp?catType=P&catString=40

That's a great point. I assumed from the question that it would be helpful to use gears to directly control the turntable, but if that isn't important than many other turntables could do nicely. I updated the answer to include the newer studless Technic turntable as that should be easier to find, allows direct drive, and isn't in the turntable category that you linked to.

That's annoying. The Technic Turntables are in the generic Technic list: http://www.bricklink.com/catalogList.asp?pg=4&catString=36&catType=P (there are small ones that also allow geared drive)


text:
How do I Build a LEGO Digestive System?
How might I build a LEGO model of a digestive system? I think it could be a good way of helping my son with a science project.
Either building plans, instructions, or any help with getting started would be appreciated.

Unfortunately, this may be a question which we will have a hard time to answer. However, you may be interested to know that Nathan Sawaya, LEGO Certified Professional, once made a heart model for an hospital. I suppose contacting an LCP for this might be overkill, but it might inspire your kid - although it probably doesn't need to be so accurate for a school project.

I would keep it very simple with just building the organs with regular bricks. Color code each organ. I have never seen anyone do this with LEGO bricks so can't link to a picture, however I can imagine than it could be done easily. Basically you would end up with a pipe-system. ;)


text:
EV3 and HiTechnic Color Sensor Block
Can I use the Hitechnic Color Sensor with my EV3?
At the HiTechnic web site I cannot find the necessary files for importing the Hitechnic Color Sensor Block into the EV3 software.

For 3rd-party product support you might find it quicker to contact HiTechnic via their support form.

Yes there is
On the HiTechnic website: => download
http://www.hitechnic.com/downloadnew.php?category=38
This is preliminary release of the HiTechnic EV3 Color Sensor Block.  Note that this block only supports the EV3 and will not work with the NXT.  Zip file includes both the Color Sensor block and a sample program that shows the color sensor values on the EV3 screen.  See instructions at top of this downloads page for installation instructions.


text:
Please identify this broken LEGO Technic piece
This piece is from LEGO Technic 8070 Super Car. Can anyone please identify its name as it's broken and I need to get a new one.

since you started probably knowing the set number, a search for "lego 8070 part list" will take you to the brickset inventory very easily.

The very first step you can do if you knwo the set number is go through the LEGO customer service where you can type the set number and see its inventory. If your part is there and is in green, you can order it directly from LEGO (usually for free if the part is broken). In this case it wouldn't have helped as the part in question is not currently in production (appears in red), but at least it helps you identify the part as well.

Sure looks like one of these: Technic, Steering Gear with 4 Ball Joints, Complete Assembly with Black Base
It comes in a handful of sets

Thank you so much for your quick response. You were right! Found the piece on ebay.

I've moved the text above the image to make it easier to see ;)


text:
How to put LEGO together upside down
I'm building a truck. For the transmission, I want to make it all even and symmetrical.
To do that I need the pieces to stay together but they have no studs connecting so they will just fall apart.
Does anybody have any suggestions to keep them together besides using the light saber shaft?
This is the main chassis for the truck.
This is what I want the transmission to look like, but it's quite big so I want it smaller. As you can see, the arch bricks won't go together this way so I need an idea to keep them together.

There's a couple of suggestions in this question where people have answered the opposite of the original question.

Technic bricks can easily be attached with the studs in different orientations. Or minifig hands can be used to attach plates back to back with no gap if you don't need a lot of stiction.

I attempt to create a searchable index of SNOT techniques, as this is called. Of those, the strongest 180 degree stud reversal are probably one of these:

If you want to connect the two curves together bottom to bottom, you should be able to do it with an axle, sort of like these two techniques:

If that doesn't work I once had luck playing around with a lever and a rubber band. It was tricky, but it did work:

I think this is how we did it as kids. However, it was 1970s. Probably too primitive, clumsy, or against the rules now.

You can build a similar design which I find is stronger (but slightly larger) using cheese slopes and a plate and brick of the same size. It can also be built with two plates and cheese slopes.

@Ambo100 Post that as an answer, it's the best one here!

Generally, the lampholder plate does the job:
http://www.bricklink.com/catalogItem.asp?P=4081b
but some idea of the scale you are working in will help get a better answer, or if you can post a picture of the model you might get a specific answer.

In addition, you can also use technic pegs to join bricks base to base.  This is an, 'illegal technique,' however, as forcing the peg into the tube will weaken/bend the plastic slightly and make it weaker in the future.

While Windfire's suggestion is valid, there are several elements with opposing studs.
Many of the parts listed on that link don't apply, but several do, including the first five.
If you're not clone-averse, Cobi makes some great plates with studs on both sides, though I have no idea where you can get them aside from buying entire sets known to contain them.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


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Are these ATC bricks from the 1970's LEGO?
I have some Lego compatible basic bricks from early 1970s or late 1960s. Bought in Finland or maybe Germany or Sweden. Can anyone tell me more about them?
As you can see, the interlocking mechanism is different, but fits with normal Lego bricks. The colours are normal Lego white, blue, yellow, red, and black, save for one piece that is bright green.

Here's another photo where you see the logo and interlocking mechanism nearer:

Note that that particular interlocking method was also considered by LEGO as evidence by this picture taken in the LEGO museum and presents some advantages in my opinion (if using hollow studs); it was also used by Tente but the larger studs make them mostly incompatible with LEGO bricks.

I've always thought ATC had to use this because LEGO patented their mechanism.

Sadly, the only ATC at that link is in the SKU, and the bottoms of those bricks looks like regular LEGO.

ATC is the Asahi Toy Company from Japan. Here are the pages from their 1971 catalog showing some of their construction sets:

Bright green 2x4 brick and blue round 2x2 exactly like in my photos. This is it.


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How can I build a Lego rubik's cube?
How can I build a LEGO Rubik's cube, I have 2 of them, and I've built them several times, but how can I build a LEGO Rubik's cube.

There is a proposed set on the LEGO Ideas site here of a LEGO Rubik's cube that is sturdier than the smaller one in @jncraton's answer. Of course, you can customize it however you wish. The center uses LEGO Technic to make it sturdy. Go to the updates tab and scroll down for instructions.

There seems to be basically two choices. You can either build a larger version than the traditional cube, or you can build something that doesn't stay together very well.
There's a nice example of a small cube on Sebastians Sand's Brickshelf:

While this looks like it would work, I can't imagine that it holds together through many rotations.
If you are willing to build something a bit larger, there are some good examples available, but it looks like it gets fairly complicated.

Here is a video on how to stick LEGO bricks on to a Rubik's cube.
https://www.youtube.com/watch?v=FrbBZ4EytHs
You're welcome.

This video shows you how to make a Rubik Cube look like LEGO rather than actually being made out of LEGO.

Downvoting because the question asks about how to build a rubiks cube out of lego, not how to make a rubiks cube look as though it was built out of lego...


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On Lego Mindstorms EV3, is there a way to change the input parameters of a My Block?
I am writing a program for which I did a My Block. I later realize that I need to add a new input parameter and I can't find a way of doing this without creating a new My Block. This seems it should be trivial but its driving me crazy not being able to find out how. Any help would be very much appreciated. Thanks

It's possible now, see https://bricks.stackexchange.com/a/9278/9277

Unfortunately, there is no way to add a parameter to an existing MyBlock in both the NXT and EV3 series. You will have to create a new one with more input parameters.


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What can I do to clean a minifigure's torso?
I have the old General Grievous figure from 2005, and it is almost 10 years old.
Due to its age, the torso now looks yellow-painted.
What can I do to clean it?

In general, legos can be un-yellowed by soaking in a combination of hydrogen peroxide, oxyclean powder (or sodium percarbonate), under sunlight or UV light. Or use Retr0Bright. Certain colors of painted decorations (such as gold) will not hold up well to the cleaning, but plain pieces and some colors do hold up well.

For regular dirt and grime a little bit of dish soap and warm water and a sponge or soft cloth should get most figures clean.  For tough or caked on dirt you may need to use a scrubby sponge or soft brush, but be you run a risk of damaging printing on the figure.  Older LEGO pieces can become yellowed over especially with prolonged direct exposure to sunlight.  Many have reported success with oxidizers such as hydrogen peroxide or oxyclean, but there is also a possibility of damaging the element.  Good luck!

Adding to user3576's comments:
Dish soap and warm water is your first choice. You can let tough grime soak in soapy water for weeks before washing if needed. Hot water is bad because ABS has a (relatively) low melting point, so a trip through the dishwasher would not be advised. Also, dish washing detergent has abrasives, so...double nope.
Yellowing due to sunlight needs oxyclean + h202 or retrobright to correct. This works, but in addition to the above warning about metalics, be aware that it take a LONG time to work, so don't expect a quick 5 min dip will start to fix things. I have left bricks soaking in the stuff for weeks.


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EV3 Rapt3r's head cable interfering with slithering
My Rapt3r is working great, except that the cable that goes from the head to the "Intelligent Brick" physically interferes with the slithering on the side on which it is plugged (port 4).
Physically interfering in the sense that the cable being somewhat stiff prevents the motor from turning all the way on that side.
If I unplug the cable the slithering is much more balanced between the two sides. Is there a better way to thread that cable than what is shown in the instructions?

That's bad. Try to unplug and plug fast and see what happens. Or try to connect the cable on the port that is beside, and then, connect it to its port. I hope that works.

Sorry, it is not a connection issue -- it is the cable itself physically preventing the motor from turning (I added some wording to the question to try to clarify).


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Where can I find LEGO Digital Designer projects for Lego Technic MOCs?
I have LEGO Technic pieces collected from multiple sets and would like to find projects on the web which I can view and build models step by step. Please advise sources where I can find these.

Eurobricks forum has hundreds of official sets in LDD format here: http://www.eurobricks.com/forum/index.php?showtopic=41226&#entry727293

As suggested on this question Rebrickable has a number of MOCs based on Technic parts.
If you happen to know which sets you have, you can create an account, add your sets, and then filter those MOCs to just ones you can build.
However, not all of these are available as LDD projects, some are "photo sets".


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Can I repair a broken LEGO brick with glue?
I have a dump truck hinge piece that snapped in half when it got bent backwards too hard. Is there a type of glue that would be appropriate to repair the piece? Would superglue be a good choice? Obviously, it's never going to look new again, I'm more just concerned about the piece being functional if we wish to build more dump-trucks. Or is it a lost cause and after I go to all the trouble to glue it, it's just not going to hold?
Here's a picture of the broken part. Ldraw seems to list this hinge as parts 3324e + 314e

Hi Jessica, you might find some of the suggestions on What glue should I use for permanent LEGO construction to be a good starting point. I'm not sure exactly which hinge piece you mean, but one of solvent based suggestions should help :)

LEGO is very good about replacing broken parts - for free even.  Visit the web-site and look on the bottom of the page under Customer Service for a "broken or missing parts" link (I can't check at current locale).
This is worth trying even if the set is old or you didn't acquire it brand new. LEGO doesn't usually care where you got the set; but if it's not recent there's a risk that the part is not produced anymore, and then they won't be able to replace it. But try anyway, they're usually very friendly.
You can also try calling Customer Service directly.

If the folks in the local LEGO store know you they might even be able to find what you're looking for in the store's spare parts bin.

This is exactly what I was looking for! Just for help, this is the direct link for UK customers: https://www.lego.com/en-gb/service/replacementparts/

LEGO bricks are made from ABS.  Therefore the most effective adhesive would be ABS cement from the hardware store that sells it for plumbing repairs. ABS cement in theory would chemicallyc weld the bricks back together.

It's sometimes possible to build a jig out of other Lego blocks to hold the broken pieces firmly together to allow the glue to set and the result to be very good.  I use my worst-condition bricks for jig building because they almost always get glue on them or some kind of damage.
The location of the break on your hinge makes it a difficult fix, but you could try to make a basic jig by:

Putting a couple layers of plastic wrap around the 2x8 portion (to keep glue off)
Using a thin 2x4 plate at the end of the 2x8 bit of the hinge
Using a 2x6 plate atop the previous plate to secure the 2x4 broken bit of the hinge in place

Then carefully align the broken hinge bits and apply a glue which will weld the break together.

I've had success repairing cleanly-broken parts (snapped without bending) using plastic cement -- the sort that contains methylethylketone.

Make sure the broken surface is free of dirt and other contaminants.
Brush a small amount of plastic cement onto both fracture surfaces.  Make sure not to accidentally get any anywhere else -- this stuff works by briefly dissolving a thin layer of plastic at the join, and can cause damage if not used carefully.
Hold the two parts together for about 30 seconds to let the cement set.
Leave the repaired brick alone for a while (I usually let it sit overnight) to let the join fully harden.

That said, your hinge is a tricky repair.  That's the weakest part of the brick, and it's quite possible the join won't be strong enough.  It's also close enough to the pivot point that you risk gluing the hinge permanently in place.


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Cost of different works in a LEGO set price?
What percentage of a LEGO set's price goes toward research, design, manufacturing, marketing etc.
It's just my curiosity since all my minifigures (from Series 3) are made in China and I don't know if LEGO has factories in China or they just outsources it to other Chinese manufacturers.

@jncraton: Thanks so much for correcting grammar errors :)

It's no problem. :)

The 2012 annual report on the LEGO Groups site states the following:

Research and development activities
  Each year, new launchings account for approximately 60% of the LEGO Group’s sales to consumers. Therefore, the Group has considerable development activities, comprising anything from trend spotting and anthropological studies to the actual development of specific products and campaigns. Approximately 160 designers from about 20 different countries make up the creative core of product development that is mainly based at company headquarters in Billund, Denmark.

It's hard to quantise exactly how much of each set goes into the various different aspects you're asking about as different sets will have different margins on them. Taking some of the numbers in the report however, you can see things like:
On Revenue of 23,000mDKK:

6,800m was spent on "production costs" (about 30%) - these are defined as "raw materials, consumables, direct labour costs and indirect production costs such as maintenance and depreciation, etc.". These are further broken down to include:

4,400m on Raw materials and consumables
1,500m on Licence and Royalty expenses

1,200m was spent on "other operating costs" (about 5%) - these are defined as "[including] royalty and research and development costs". This is further broken down to include:

451m on Research and Development

6,100m was spent on "Sales and distribution expenses" (about 27%) - these are defined as "costs in the form of salaries to sales and distribution staff, advertising and marketing expenses as well as depreciation, etc."

In terms of where parts are made, this answer covers most of it, but as you rightly note, Minifigs, and some painted parts now come from China. In terms of R&D, this answer talks about how new pieces could come about.
Updated: Some of the actual break-downs in here come from the "2012" columns in the 2013 report.

So it's about 30% on production/manufacturing cost, more than I've thought. I've also heard that paper box often costs 10% of set price, and ABS plastic is cheap so it's surprisingly that box might cost more than bricks inside it :). Thank you.

Not 23m DKK but 23,095m DKK, which is a thousand fold more! In USD, that would be $3.5 billion.
And from 2013 report, the revenue was 25,382m or $3.9 billion.

Good catch @Ron1 - I've updated the figures - however the percentages haven't really changed.


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How to locate objects, and move towards them, without pre-programming the path
So I need to find objects in an enclosed area, I have access to the standard set of NXT sensors, i.e. ultrasonic/light.
However, the ultrasonic sensors seem to be very unreliable and erratic, in regards to finding objects accurately.
I cannot pre-program the path to the objects, so I'm trying to work out how is the best way to go about locating these objects?  The objects are small, and on the floor.
I was thinking a sort of swivel motion at the start, to find any objects using the ultrasonic, and then just moving a small distance at a time, then swivelling again etc.  Are there any other better ideas?
Also, there is a wall enclosing the area, would there be a way of programming the NXT to avoid it?
I'll be programming the NXT in NXC.  Can't afford LIDAR :(

In my sensor tests today I found that the ultrasonic sensor just returns 255 if there is no value to return (cable unplugged, or just no answer ready yet). So just filter those out – while ((i = SensorUS(IN_1)) == 255) {} should do the trick. Maybe that helps increasing reliability?

Oh I didn't know that! Thanks for sharing!

If the ultrasonic cannot echo-locate the objects because they're too small, even with the sensor suspended very close to the floor, I suggest using a very sensitive feeler out front. It can be sticking forward like a jousting lance, and your robot can swivel back & forth while traveling to scan.
The trick to making it very sensitive is to:
(1) make it pivot at its base on the front of the robot with a smooth pin,
(2) make it long and lightweight (use long axles),
(3) mount two opposed touch sensors as close to the pivot point as possible, and
(4) pre-load the touch sensors such that minimal travel is necessary to trigger each one.
The same techniques can be applied with a large diameter roller out front (like a steam roller) to detect any bumps on the floor (if the objects are kind of flat).


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How much are large retail LEGO Minifigures worth?
I have an extra large LEGO figure (approximately 19 inches/48 cm tall) that I wish to sell.  This is an item which has only been available to retailers as part of merchandising the stores.
Any ideas how much these are worth?

I think you should restructure your question so that it we can apply the answers to a broader audience, this question seems to me like it will only bring answers that will fit your situation.  you should ask something like "How would you figure out the worth of a Lego Figure?" or "what kind of information is needed to determine the value of a certain set of Legos?"

pictures would be good too...

These typically go for several hundred USD at the low end, and can be up to several thousand for the rarer display figures.
One way to get an idea of the current market price is to check out the items currently for sale on Bricklink. A search for 'display figure' in the gear category should give you a pretty good idea.

I have been making a list of these over the past few months.  I have about 43 and I think that another 50 or so exists.  You can see the full list here. http://www.minifigpriceguide.com/MAXIFIGS.0.html
I think that these figures generally go for between 400 - 1500 depending on the character.  The last Spiderman Doc Ock combo that I saw went for around 3000.

Hi Logan - any chance you could include a currency in your answer - 400-1500USD is fairly different to 400-1500GBP and is very different to 400-1500DKK ;)


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Minifigure Torso Cracks
So I recently picked up the new Star Wars AT-AP and I was quite please with what I got, but after not even a week The awesome Commander Gree Figure had a torso crack that went from the bottom of the left side to About halfway to the top. It was put together and put on a shelf. No kids played with it or anything.
Is this because of the legs stretching it out or has the quality of LEGO decreased? Also how can I fix this without using glue?

This is possibly a duplicate of Repairing LEGO minifigure torso cracks/damage

Given that this is from a new set that is currently in production, you should contact LEGO customer service and they'll probably send you a replacement torso at no charge. LEGO has a pretty simple site to handle this:
https://service.lego.com/en-us/replacementparts#BasicInfo
You just have to enter your age and the issue that you are having, then you enter the set number (75043 in this case) and find the piece that is broken from the parts list. I just checked, and that torso is currently listed, so you should be in good shape. I've had this same torso issue, and they were happy to send a replacement.


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Which bricks warrant an extra to be included in a set?
I know why there are extra pieces in the sets, but I'm curious to find out which pieces will typically have an extra.
I know that usually 1x1 plates (both square and round) will have an extra included in the set, as well as cheese wedges. But I was surprised to find an extra double cheese wedge included once (I don't remember which set it was, but no, it wasn't a piece I overlooked in the building instructions). I have other sets with double cheese wedges that didn't have an extra, so I wonder:
Is there a list of pieces that will usually come with an extra?
Are there other criteria used to determine whether a piece will have an extra?

The inventory of parts provided for sets on Bricklink show which parts are considered extra. It might be possible to calculate which extra parts are the most common across the database of sets.

It's highly variable. I've had some sets with some of the smaller piece and ZERO spares. On the other extreme, the 2013 Star Wars advent calendar had up to THREE spares of the usual pieces and even bigger than usual (cups, beards) pieces, bringing the total number of pieces to nearly 150% of the number stated on the box.

Back in the day, it was because some of the pieces such as 1x1 round plates or flower petals came still attached to the sprues -- 1x1 round plates would always come as a multiple of two, while flowers would come as a multiple of four.

@Mark you're right! I had totally forgotten.

The ones that come with extras are almost always the smallest pieces in the kit that would be easy to lose and are negligible in weight.
From gizmodo article of LEGO FAQs:

Why did I always have pieces left over when I built my castle sets? Do they just do that to jack with kids?
For two reasons: first, because some pieces are so small that they weigh too little to be measured by their scale, during packaging (you will see this when I publish the factory tour. J.) Second, because it's better to have too many of those pieces than have one of them missing. Since we statistically know what pieces may get lost, we include some extras when appropriate.

thank you Zhaph-Ben for the edit. I couldn't figure out how to make the nice quotation box on the android app editor.

PS: the url of that FAQ is http://lego.gizmodo.com/5019797/everything-you-always-wanted-to-know-about-lego

It's all about knowing the markdown which still works in the app ;) But yes, it's certainly more bare metal when you're in the app.


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What different types of LEGO train tracks exist?
I would like to purchase some used LEGO train tracks off of ebay. I am not, however, very familiar with the different choices of track systems are out there that I might come across. So I would like to learn more about the existing types of track systems. What kinds has LEGO used at various eras in their history? Are they inter-changable? If I'd like train tracks that are compatible with the currently available new LEGO city train sets, what types of tracks should I consider?
If possible, I'd love to see photos of a basic piece of each kind side by side to see the differences.

The main LEGO train systems are all roughly compatible. They all use a 6 stud gauge, so with a bit of fiddling, you can use all of the systems together. If you want to be most compatible with the current track offerings, you're better off with 9V and RC/PF track. This question discusses the specific compatibility issues in more detail.
There are several other train systems that have been used that are not compatible (DUPLO trains, 4 guage rails, etc), but I'll just cover the common 6 gauge systems here.
The different types of train track can be divided into a few main eras.
Blue Era (1966 - 1980)
A track section consisted of 2 rails connected by regular 2x8 plates. The rails themselves were blue.

Trains could be either pushed by hand along the track, powered via 3 batteries (4.5V system), or powered via a third conducting rail added to the center of the track (12V system). Here are what the conducting rails for the 12V system look like:

Some people still prefer the 12V system because it included more remote controlled components than the later 9V or RC/PF systems. With later systems, the only thing that is easily remote controlled is the train itself, whereas the 12V system included remote controlled points, light, and decouplers.
Each era included straight track, curved track, switches, and cross track.

Gray Era (1980 - 1991)
These rails are generally the same as the blue rails aside from the new gray color.

The sleepers were moved closer together (3 per section rather than 2), and they were changed to a specialized part to improve the strength of the connection. Here's what the sleepers look like:

The trains of this era were still either powered by 4.5V batteries or the 12V conducting rails.
9V Era (1991 - 2006)
The 9V era completely changed the track components, and did away with the old 4.5V and 12V voltages. Rails sections were a single piece, and they were all conducting.

The 9v system included straight, curved, switch, and cross track.

RC / Power Functions / Powered Up Era (2007-)
In 2006, LEGO switched back to non-conducting rails with roughly the same mold as the 9V track. Trains are now all battery-powered under either the RC or currently the Power Functions and Powered UP systems.

This era included the first and only crossover switch (7996) :

It also introduced flexible track:

Switches are also available, but a cross track has not yet been released for PF track.

they should bring back the 9v track, would make trains way easier to build


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Part Identification - bricks with posts
I have two unusual lego pieces that came from a collection of used legos that mostly seem to date from the 1970's that I am unable to identify using LDraw's ldfind app. What are these parts, and if known, what sort of sets might they have come from?
The red one is a 2x6 plate with only two knobs on the top of the plate, with a triangular post with that is about three bricks tall with one knob on top of the post. The bottom of this brick says "Pat. pend" and has A and 1 designations.
The black one is a 2x4 brick that looks like a wheel brick with holes on the sides that might be for wheels, except on top there is a tall post and two short knobs. The bottom of this brick says "Pat. pend" and has E and 4 inside the circles. It sort of looks like a technic post, but thicker.

The black piece is part of a steering mechanism, part of 377-2: Crane With Float Truck. Here it is on BrickLink.

Like Windfire says, the red part is a direction switcher. You can see the switch on the side of the battery car.

I had that crane set. I'd cry, but aside from nostalgia value, my lost childhood LEGO collection is a drop in the bucket compared to what I have now. :P

Nice work figuring it out! I recognize several other unusual parts in my collection such as the string wheel winch, odd shaped hinges and baseplates which makes me even more confident it's a correct match. :)

The Red piece:
Bricklink number 3218
http://www.bricklink.com/catalogItem.asp?P=3218
4.5v direction switcher for trains.  Works with a long switch on the side of a special train brick that hits the triangular post, moves and then reverses the motor.
The black piece is still a mystery.

That would be fitting that it goes with a 4.5 volt train sets. There were some other assorted parts in the lot that also appear to potentially be the remnants of a motorized train set.


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Are there any LEGO elements not being produced because of mechanical problem with the mould?
I am referring element number 702 4x4 corner brick, and possibly other elements that have not been in sets in a considerable amount of time.

The 4 x 4 corner brick really isn't useful, and can almost always be substituted with other bricks. Given its limited utility, I imagine that replacing old moulds just isn't cost effective.

I've been wondering the reasons why a number of pieces are no longer available and it appears the decision to reduce the overall amount of different pieces is simply a cost based one.
From a Q/A with someone from the Lego Company:
"...the piece count has been reduced drastically and there's a move back to roots in Lego, not only for creativity but to save money. Lego went from 12,000 different pieces to 6,800 in the last few years-a number that includes the color variations."
snippet was from here:
http://lego.gizmodo.com/5019797/everything-you-always-wanted-to-know-about-lego


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How does cleaning yellowed Lego bricks affect their clutch power?
Will cleaning yellowed bricks (via the retr0brite solution) decrease the clutch power of lego bricks?
I've also heard that certain colors of embellishments on the minifigs or bricks do not hold up well to this solution, is there any definitive list of colors that do/don't hold up well? I have some old white bricks with red and black printing on them that I'd love to unfade if it won't wipe out the lettering.

The retr0brite method only affects the surface of the brick and does not affect the clutch power.
I have used the method on several printed bricks. I have noticed the black printing will start to fade if the bricks are left in the solution for a long time. I have not noticed that it affects other colors as much as black, but this may be because the fading of black ink on a white or yellow background is more obvious. I have never seen the treatment completely erase any printing.
The length of time it takes the solution to start breaking down the ink is going to vary with the strength of the solution, the time in the solution and the amount of UV light. You can control the first two variables, but if you are using sunlight to provide the UV it is difficult to gauge or control.
The easiest variable to control is time. I would leave the bricks in the solution for perhaps an hour at a time, then take them out, rinse them off in water and dry them. Keep one of the yellowed bricks as a "control" against which you can compare the treated brick to get an idea of how much color has changed. Repeat as necessary until the brick is back to the color you want or you notice the ink beginning to fade.
Check the color of the bricks indoors. I use the sun on my front porch to provide the UV light when I'm soaking bricks, and I have noticed that bricks that look nice and white when I'm out in the bright sun will still appear yellowed when I get them inside.


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Why do some sets contain parts of an unrelated colour that are hidden on the final model?
With recent and current sets, I noticed that some contain parts of a totally different colour than the rest of the set. An example is 8200-1: Radiator Springs Lightning McQueen, which contains a blue 2×6 plate, 3 yellow 1×2 plates, 2 white 1×2/1×4 angle plates, and 2 grey 1×4 plates, while Lightning McQueen is red.
Parts like these aren't usually visible in the finished model.
Why are they used?
These are parts that should be available in most colours, including red. Did they have an overstock in these colours? Is it to make for easier building? Since this way both the model and the instructions aren't a big blob of red?

I believe the main reason is so that the pieces are easy to identify in the instructions - as many LEGO sets don't have the Technic style "List of elements used in this step" it's always a fun game of "Spot the difference" to see what's changed:

If those pieces were all red, then the target audience (5+ on those sets for example) might find it very frustrating to build.
(Even with the list of elements to use in a step it can often be quite an effort to find where a particular part goes.)

One thing I've noticed is that many models go one step further: not only are certain parts in unrelated colours, but sometimes all the parts of that size/shape are the same colour, making it easier to find the part in the pile of unused parts.

its interesting that even on the BTTF and Ghostbusters that do have the parts list that they still do that - the BTTF wheel catchers were both red and blue.

@Mr.ShinyandNew安宇 That's probably so they minimize the number of unique parts in a set. I've noticed they'll occasionally combine smaller bricks to make a single instance of a larger brick a few times per set for this reason (I assume) as well.

@Feathercrown yes. There are several competing factors at play regarding the cost of parts, and sets are always trading off certain things against cost. The precise calculations are secret, but also, sometimes cost isn't the deciding factor, such as in certain sets where they specifically throw in extra of certain elements so that they can give fans more of them. An example is the 1x3 dark green tile, which Jamie Berrard (the designer) explained was abundant in the Sopwith Camel set so that fans could have lots of them to use afterward.

One reason is ease of identification, even in sets not intended for the youngest age range.
For example in the Millennium Falcon 7000-piece "mega set" all the 1x16 Technic beams are dark grey, the 1x14 are black, and the 1x12 are light grey. There are about 70 of these beams in total. Almost all of them are invisible in the final model since their main purpose is to give the model its structural strength, but it's an easy way to sort them. There is a similar color coding for the longest "1 x whatever" bricks, as well.
In the same model, the half-built structural frame is almost symmetrical end-to-end, the sides are mirror images, and it is almost identical when turned upside down, but a small number of coloured parts make it easy to orient it correctly and avoid discovering a mistake after many building steps.
Some color coding seems almost universal across sets - for example black and blue Technic connector pins. Again, an easy way to avoid mix-ups when building.

Indeed - the pins were a long-running colour convention - it used to be black and grey (friction and non-friction), but even those are available in a number of different colour combinations these days!


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What is the correct input voltage for the 9v Lego train speed regulator?
I wanted to buy a transformer for the speed regulator, so based on this image, I bought a transformer with 12V DC output. It works.
However, discussing this with a fellow AFOL, he pointed out that his (original from LEGO) transformer has a 10V AC output, as seen in this image.
So... which one is correct? Or they both work? Or there are different versions of the speed regulator with different input requirements?

My speed regulator is clearly labeled as being 9-12V AC. I have an official 12VAC transformer.

I was curious about the internals of this device, so I opened it up:

The circuit begins with 4 diodes in standard bridge rectifier configuration. This converts the AC input into a rippled DC voltage. The large capacitor (2200uF, 25V) then cleans up the ripples. There is also an LM317 adjustable voltage regulator configured to output various voltages depending on the dial setting.
This means that the input can be 9-12 voltes AC or DC because the rectifier simply passes DC current.


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When and why were pieces 3651 and 3652 discontinued?
Bricklink has piece 3651 as Axle and Pin Connector, while piece 3652 is Engine Piston Square 2x2. You could attach them to each other to form a piston.
Service pack 5260, Connecting Rods and Stop Bushes, has them together in a set.
When were they discontinued?
Why were these useful parts discontinued?

3652 Technic Engine Piston Square 2 x 2

This part was included in sets from 1977 until 1995, but it began to be replaced by 2851 starting in 1990:

The main advantage of the newer piston is that it allows more pistons to fit in a smaller area of space. The piston is able to fit into the 2850 2x2 cylinder:

The old piston required a brick-built 4x4 cylinder, so the new part allows for either smaller engines, or engines with more pistons in the same amount of space.
Imagine how much space it would take to build this V8 using the old style of piston:

3651 Technic Axle and Pin Connector

This part was technically available in sets from 1977 until 2003, but it was generally replaced by 32013 starting in 1997:

This was part of a general overhaul of Technic axle connectors that replaced 4273 with the angled family of connectors (32013, 32034, 32016, 32192, 32015, and 32014).

Hmm, the new ones clearly look more "realistic" if that's what you're after, but I personally find the original ones to be more useful in a "sticky piston" kind of way ;) And when you add in the bulk needed for the pegs, you're only saving in one dimension...

Also, the old piston allowed to attach something to the top of it. I once made a space ship go up and down that way. But I really miss the studs on the side of the connector, they were very useful. Those connectors use with a 1x10 plates made for nice barriers, to name just one use.


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Types of instruction manuals
I noticed there are 4 different types of instruction manuals (at least for large sets):

Type I: Similar piece colors are not very distinguishable (especially Dark Gray and Black). Some building steps could be clearer (for example, adding arrows or changing the point of view). Similar-looking pieces are sorted in the same bag. Bags are not numbered.
Type II: Same as Type I but with numbered bags.
Type III: The piece colors are a lot closer to the actual pieces and are easily recognizable (Black has even a white outline). All building steps are better described. Pieces are better sorted in the bags. Bags are numbered.
Type IV: Same as Type III but with the pieces to be added in a given step outlined in yellow or red.

One could think of a type to be an improvement over the previous one, and when a new type is released, the old one wouldn't be used anymore. But that's not the case.
Here are some sets with their corresponding type:

Mobile Crane (8421) released on 24-Oct-07 is of Type II.
Death Star (10188) released on 21-Jun-08 is of Type I.
Pet Shop (10218) released on 12-May-11 is of Type II.
Town Hall (10224) released on 03-Mar-12 is of Type IV.
Palace Cinema (10232) released on 01-Mar-13 is of Type III.
Mobile Crane MK II (42009) released on 27-Jul-13 is of Type II.
Maersk Line Triple-E (10241) released on 01-Jan-14 is of Type IV.
Parisian Restaurant (10243) released on 01-Jan-14 is of Type III.

Do you know why the manual types are not in strict chronological order?

Let us not forget there are also instructions with or without part boxes.

I remember that in the 80's black technic parts where always hard to recognize in the instructions, in those years you had to count the studs yourself. Over the years black became a little lighter in colour to a dark grey. This was also shown on one of the first pages of the instructions.
This stays OK until the introduction of dark grey parts. At that point LEGO struggled again with colours in the instruction. This was around 2008. In the year later this was solved by making black darker again. This current colour scheme is used in for example 42009. So this set is not a type II but another type. Also LEGO nowdays try to keep the same parts both in black and dark grey to a minimum per set.
Until now I never noticed that LEGO uses two different ways to show black parts. With and without a white outline. And also on the PDF's instruction it look like the shade of black is different. I don't know the reason for this and if the white outline is only used for non technic sets.
Numbered bags are used through the whole line of sets. And make the building a little easier by reducing the number of parts to look through while finding the part needed.
The coloured outline on the build steps are used at least from 2000. These are often used in larger models like 3723-1: LEGO Mini-Figure, where it can be hard to see where a part go. Often because of the uniform colour of a model.

I would hypothesize that, perhaps, it's not a matter of one style being the "official" current style at a given time so much as there are probably multiple individuals or teams that write the manuals for assembling the models, each of whom have a slightly different writing and illustration style.


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What is this upside down roof peak or boat hull?
Here's another mystery piece from my collection. I'm not 100% sure it's genuine LEGO, but I would love to know whether it is, and if so, what part. It attaches to the bottom of a 2x8 brick securely. No markings to identify branding or part numbers, but other legos it came with were from 1970s era.
It kind of looks like it ought to be a curved roof peak, except it's upside down. Maybe the bottom of a boat hull? But what about the notched slots on the bottom?

* there is a small crack in the narrow end of the brick. The left side is what both sides should look like.

It looks to me like this is a Weighted Keel 2 x 8 x 4 (x149). I don't personally have this part, but it looks like your part is this part broken in two:

These were mounted under the floating boats of the late 70s and early 80s.

The missing bit is the actual weight. (I have this part).


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How can I controll the speed of motor using gears?
Can anyone tell me how to use gear wheels to modify the speed of the motor in the Power Functions set 8293?
I know I could use the remote control unit, but I need to have a fixed slow speed on a static unit which will power a non-LEGO moving toy. I need a slow turning axle.

Sariel's tutorial is one of the better ones, and his whole web site is worth while. The Eurobricks Technic forum also has a list of tutorials thread that you might find helpful.
Sariel starts very simple and ends up with a discussion of what makes different variants on some of the Lego gears effective...


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Large LEGO Minifig Styles
I'm pretty sure the LEGO figure on the right is the daughter from a 1977 set Nurse and Child. But what about this style of jumbo minifig on the left with arms and legs that bend? When was that from? It might be from a LEGO Basic set? What different styles of minifigs has LEGO produced over the years?

The figure on the left is generally referred to as a Fabuland figure, although I believe that the entire Fabuland line actually featured animals. There were a few basic sets released in the 80s that included human Fabuland-style figures. That one is probably from this fire engine:

Before the introduction of the Minifig in 1978, there was the Maxifig that you noted in your question:

The precursor to the modern minifig was added in 1975:

LEGO released a history of the minifig that you might find interesting.
In addition to the traditional minifig, you may also come across Technic figures which were around for a time.

There were also the Creator figures that were only around briefly in the early 2000s:

The Creator figure look very similar to the ones in the Jack Stone theme.

The link for the timeline is broken, not even a 404 page appears.


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On what plane is 7292 Propellor Adventures based?
The set 7292, Propeller Adventures, features a twin engine airplane. It looks a bit like the de Havilland Mosquito, but not quite.
On what plane, if any, is it based?

Related: Help Identifying a LEGO plane

It looks like a pretty generic twin engin-ed WWII bomber.  Maybe like this Mosquito bomber?

I have always made the connection to the Mosquito.


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On what plane is 6912 Super Soarer based?
The set 6912, Super Soarer, features a yellow jet plane. My first thoughts were towards the Harrier, but it has exhausts on the tail, which the Harrier doesn't have.
On what plane, if any, is it based?

I think "inspired by" is a more accurate question - there are a number of aspects of this model that are "similar to" but not identical to real planes.

I would go for another British aircraft: Sepecat Jaguar
It's twin-engine also.

The intakes, wing shapes and overall proportions look like a Harrier Jump Jet, but the model doesn't have the landing gear or under-wing armaments.
Similar overhead view of a Harrier:

The Harrier was the first one that came to my mind as well, based on this picture. But, as can be seen in , the _Super Soarer has exhausts on its tail, which the Harrier decidedly doesn't. I've added a picture showing this to the question.

The lack of armaments probably comes from the fact that LEGO tend not to go in for "war" directly as well as the fact that someone else owns the license for "HM Armed Forces" based construction toys


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Trouble finding plastic storage bins for MOCs built on 48x48 stud (gray) baseplates - Ideas?
I have a number of models built on gray baseplates that are that are proving to be difficult to store/transport. Lidded plastic bins would be ideal, but I'm having a lot of trouble finding bins with these criteria:
• Flat bottom (no ridges, wheels, etc)
• 15-16" square on the inside bottom, to hold the baseplate
• Approx 6" deep.
• With lid, preferably one that clips shut.
There's one hiccup: I'm in Canada, and Amazon/manufacturers don't seem to ship these items here. Any suggestions of particular bins, or where I could get the ones listed below would be great.
Some bins I have seen and considered, that may work if I can find them:
Lego Dacta X-Large Storage Box (#9920)
http://lego.wikia.com/wiki/9920_Yellow_Storage_Box_with_Lid
- Very hard to find, since they're quite old.
Iris Buckle-Up Box 33 QT BCB-SQ Clear
http://www.shopirisusa.com/buckle-up-box-33-qt-bcb-sq-clear.html
- Best non-Lego one I have seen so far, but I haven't figured out how to get it in Canada.
Really Useful Box 50L
Taller and longer than I'd like, but it could work.

The two solutions I've seen are to measure the size you want and visit places that sell a variety of storage bins so you can find one the right size. In Australia we have a variety of bins about the size of a milk crate or beer crate (about 12" by 9", from back in the day when those units were relevant). The modern plastic equivalents with solid walls and floor will hold a 48 square baseplate quite well, and are designed to stack.
A search for plastic storage container canada suggests that there are chain stores in Canada that sell things like this.
The other solution is to make (or have made) some wooden boxes. A woodworker will be able to cut 6mm or 9mm plywood up and make whatever size box you want and reinforce them a little so they can be stacked. Then you buy chunks of foam and cut them to suit your models. Or just make "bricks" in a range of sizes to pack around random models. The advantage of this is that you get boxes exactly the right size for your models. Using cut to shape foam rather than foam peanuts means that any small parts that fall off are easier to find.
When putting multiple models in one container I prefer to put each in a plastic bag, again so that any parts that come off are easy to find and are associated with a specific model. Opening a big box with several models in it and finding a layer of small parts in the bottom is disheartening not to mention tedious to fix.

Your input about packing technique is especially helpful. Thanks!


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Creating a native EV3B block
I'm trying to create a native block for a hardware sensor. I've got it working pretty well, but can't get it to show up in the "port view" as anything but a sound sensor. I really need the live view of the data the sensor is seeing. Is there an example of how this is done that I could follow?

The answer is: you can't.
The EV3 brick detects which type of sensor is plugged in to the ports by examining the electrical characteristics of the sensor1. Electrically, all NXT Analog sensors look pretty much the same, so they will all be detected at the LEGO NXT Sound sensor (or possibly the LEGO NXT Light sensor - or a very, very small chance as the LEGO NXT Touch sensor).
So, take @momrobo's advice and write a small program that simulates the built-in port view.
Or, if you are really ambitious you can create an adapter so that the sensor will look like an EV3 type analog sensor instead of an NXT type analog sensor. How do to this would be better suited to a blog post.

instead of the live data on the port view you can make a small program which contain you sensor block and a display block and make you sensor block send its data to the text display block so you've made your own port view.

You Can't
EV3 Port view is a simple program 'downloaded as application.
It can only use certain original sensors.
You would have to make your own program. If you want it in the same section, you can use an option called 'download as application'.


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What products, if any, have ever been recalled by LEGO?
The question says it all. Have there ever been any recalls of products by LEGO? If so, what were they?

There is a list of recalls dating back to 2002 on the LEGO site, so that's a start.
It contains two items:

A specific version of the IR remote, typically used for trains.
A one piece toy truck, only sold in the USA.


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Will LEGO Caboose (10014) work with LEGO Cargo Train (7939)?
Will the older LEGO Caboose (10014) work with the LEGO Cargo Train (7939)? I wonder if it will fit the newer track and if the magnet couplers will still work?

Welcome to Bricks, Amanda!

Track
As  a general rule, the rolling stock from all LEGO trains will work with all types of LEGO track. So, the Caboose you've mentioned will work perfectly with the track supplied with the Cargo Train.
There are a couple of exceptions to this rule:

Duplo track isn't the same gauge as LEGO track, so you shouldn't expect it to work (although you can usually get away with it anyway).
There are now two gauges of LEGO track, the traditional "L-Gauge" track and a newer narrow gauge. They are, obviously, incompatible.
Trains that were not designed to run on rails obviously won't run on rails. Sadly, this includes the unmodified Ghost Train (9467).

Electrical components are a different matter. Trains that need a powered rails obviously won't work unless they're running on compatible track. So, the old mains-powered 4.5V, 12V and 9V engines won't work on modern track unless you replace the motor (which can be non-trivial).
Most battery powered trains will be fine on all types of track, although the very early trains had small teeth on their wheels to give them traction against corresponding notches in early track. Although they'll certainly fit the modern track, you might find that they don't run very well unless you swap the wheels.
Couplings
The couplings on LEGO trains have always been at the same height, so there are no problems there. The bottom line, then, is that the couplings on the Caboose will work well with the Cargo Train.
The magnetic couplings are generally compatible with each other, so you won't have any problem there, either. The first magnetic couplings were polarised - north and south (red and blue) - so you had to make sure the wagons were the right way around on the track. 9V era trains had magnets that flip round, so they would work whichever way around they were, and were completely compatible with older polarized couplings. The very latest couplings don't swivel in the same way, but are reportedly backward-compatible with all older couplings.
(Of course, the early non-magnetic couplings are incompatible with the magnetic ones, but can usually be replaced with a magnetic coupling without too much difficulty.)
The one problem that some people have encountered with magnetic couplings is that they don't always hold together if the wagons are too heavy. This can happen if your train is too long, for example.
TL;DR
The Caboose will work well with the Cargo Train.

Could you expound a bit on this difference between "L-gauge" and the new narrower one? While I have a handful of train sets, I've never really run any of them on track, but I have a lot of LEGO train buddies and have never heard them talk about this discrepancy.

Narrow track is just 4 studs wide, whereas regular LEGO track is 6 studs wide. The range of narrow track is currently limited to curves and slopes: no points, cross-overs nor even straight narrow track(!) has appeared in sets to date. Here is an example of the narrow track: http://rebrickable.com/parts/85976/Train+-Track-Plastic+-Narrow+-Curve


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Cell phone holder
Is there build instructions for an interesting cell phone holder that can be placed on a table? The holder needs to hold the phone upright and allow it to be charged at the same time.

What kind of phone? Different models have their charging ports on different sides.

I found a very generic one here from Instructables.com. Probably better examples out there that can be customized to your needs.


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Opaque bricks with no center post?
What is the purpose of 1x2 red bricks without a post inside the brick? I know they often leave out the middle post on transparent bricks to make them look more window-like, but what about in opaque pieces? I have a few from bricks of this type that are probably from sets from the 70s/80s but I'm not sure what sets they came from, let alone what clever things you can do with them that you can't do with a regular brick of the same size.

I'd wager it was mostly to save plastic. Many of the 1x family of bricks used to come with far fewer posts inside, like so: http://www.bricklink.com/catalogItem.asp?P=crssprt02 but notice they quit making that style in 1969.

A comment on this thread got me headed in the right direction of research. Before 1958, none of the bricks had tubes inside, though as gev points out, some of the larger bricks had horizontal cross beams. In 1958, Lego applied for a patent for a new design with center posts in the bricks, which allowed for a tighter more stable fit. So, the 1x2 brick without a post is likely a very old lego, and not a specialty piece of some sort. This was certainly not an effort to save plastic, but simply the idea of having a center post hadn't been created yet.

There might be several reasons for leaving out the central post:

For bricks with a cut-out for wires passing through.
To be able to attach a 1×1 piece underneath centrally.I
Also enables a 1mm shorter 1×3 Modulex brick to fit underneath postless 1×2.
Lego didn't add the posts when the 2×X bricks got their tubes, and there are still no posts with some having end pips.
Photo: church with light fitted inside, œlephant with bottom 2 of 1×1 bricks central on trunk, a few 1×3 Modulex, 1 with System 1×2 on top.

History, pat. pend. period started with tubes in 2×2 or more in 1958. Pips hidden away on a corner, then bricks got end pips, then pat. pend. obscured till stud pips used.


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Massive collection given to our charity
I work as a volunteer for Cancer Research U.K. We have been donated massive amounts of vintage Lego.
Could you please advise how to sell.

BrickLink or eBay. You could get significantly more if you go through the lot and separate out full sets then sell them on BrickLink. But if you don't have the time at least take a lot of really good pictures - in this case an eBay auction would be the better choice.

Brick Link is a site for buying and selling LEGO. Although it focuses on LEGO fans, who will take the time to enter each piece separately, they do have the option to sell 'unsorted lots', so perhaps that's an option for you.


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How to differentiate Cellulose acetate vs ABS LEGO bricks?
If one had a large tub of old LEGO brick, with some pieces going back to the 1950s, but all mixed together, are there any distinguishing features or appearance to the 1950s cellulose acetate bricks compared to the newer ABS plastic? Do the plastics look different somehow? Or would you just have to look for other features like lack of studs, flat bottoms on 1x1 round pieces, etc?

You don't mention if you know the source of the pieces in question, but I see you are in the US. If these are bricks purchased in North America, they probably date from the 1960s, when LEGO sets were first sold in the US and Canada.

yes, they are from the US. many of the pieces came from a collection at a thrift store. Some may have come from relatives as well

LEGO switched from cellulose acetate (CA) plastic to ABS plastic in 1963. They continued to distribute CA pieces in sets until their existing supply was exhausted, so during the transition beginning in 1963 both types of pieces were sold in sets. In North America, LEGO pieces were manufactured beginning in 1961 under license by Samsonite, which continued to distribute CA pieces mixed in sets until about 1970.
Distinguishing CA from ABS pieces based on intrinsic criteria is something of an art.
The first thing to look for is warping. CA plastic is much more prone to warp than ABS, which is perhaps the main reason the switch was made. If you find an old piece that is warped, odds are it is CA. You can check for warping by placing a piece on a flat surface and checking for any "wobble." Another good method is to build a simple brick wall with the pieces and look for gaps or poor connections.
Generally CA plastic is much shinier than ABS plastic when it is in good condition. CA pieces will lose the shine with wear, so this is not always possible to see.
There are also some tell-tale clues in the colors.

Red CA pieces have more orange than the ABS version.
Yellow CA pieces are not as bright as ABS pieces.
Blue CA pieces are a brighter shade than the ABS version.
Black, white, gray and clear CA pieces are harder to differentiate. Transparent CA bricks can be somewhat brownish, while later transparent bricks, made from polycarbonate, can have a bluish cast.
Green CA bricks are very scarce, but some green plates are CA.

Just noticed this - "clear" bricks would never be made in ABS because it can't be made transparent ;)

Yes, you're right - Edited that to make it more, uh, clear.

As 62Bricks has said, this can be an art.
Based on my experience (in the UK):

CA bricks tend to have less clutch (stickiness to other bricks) than ABS bricks. I'm not sure if this is because they are more prone to wear, because they tend to warp or just because they're old and worn out. Nevertheless, some of my CA bricks are so non-grippy that they're all but useless.
Due to their age, CA bricks have older logos and are made using older moulds. For this reason, they typically have an older LEGO font on the studs, for example.
CA bricks are more translucent than old ABS bricks. (Although recent ABS bricks can be somewhat translucent, too).
Many parts have only been produced in the post-CA era, so will only exist in ABS. Similarly, some older parts have never been produced in ABS, so will only exist in CA.

To sort ABS bricks from CA bricks can sometimes be difficult. What helps is they SOUND differently. An ABS brick emits a higher pitched sound when dropped than a CA brick which sounds more like a "thud". So if you are not sure, drop the brick and the sound will tell you what it is.

The blue looks dull, other ways to sort are:
No pips & don't hold together well are old so CA.
End pips & flowrib & 'pat. pend.' maybe CA or ABS.
Stud pips instead & no flowrib again are ABS, now made with cross support on 2×3 & 2×4 as well as on the bigger bricks.
As for ×1's, no pillars old, then pillars, then full depth cross support, then back to as before but now on all pillars.
So sort into 4 types; no pip (little mark on end where mould filled, or middle 2 letters on 1 stud of 'LEGO' faulty), with end pips, with stud pips, & stud pips + cross support for 2×3 & 2×4.
Looks like a hypocritical question, so not matter where you are. Before 1958 no tubes.

This answer would benefit from some photos demonstrating the differences you're trying to describe.


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Small LEGO train sets on narrow gauge track?
Will LEGO sets such as "LEGO Christmas Train" 40034 or "Emerald-Express" 31015 run (manually) on narrow gauge LEGO track? These sets use a wheelbase that is only 4 studs wide and wheels that have a groove in them.

It might work as is; but if not, you can certainly replace the wheels on 40034 with small train wheels, as seen in about every set featuring narrow track. Chance is, if you've got narrow track, you probably have some of these wheels anyway (unless you got the track from the flying saucer); but in any case these wheels aren't that hard to find. Not sure three sets of wheels in a row would work though, so maybe you'll need to remove the center ones.
For 31015 this might be a bit more complex to replace the big wheels, but maybe regular train wheels might work here. Again, having too many wheels in a row might be a problem as the narrow track curves are very short.


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LEGO plate with square holes?
I have some white plates with square holes on the underside. I'd almost think they were some imitation brand if they didn't have LEGO stamped on the studs. Can anyone tell me the history of when square hole plates were produced and for what purpose? Is this just a really old design? Why were they changed?

Those would be Waffle Bottoms, which seem to have been mostly phased out by 1969, except for the 4x8 plate that went until 1971. Having not read any deep history on old LEGO designs, I'm going with that was just what they went with to start, then realized that the tubes were much better.


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Is there a way to buy printed pieces to replace stickers?
I don't like stickers on my lego models. Does lego sell pieces with custom printed designs, so I can have newer lego models with all printed pieces like the old days?
If not, how do I print designs on lego pieces?
Every time I look this up on google I get a bunch of results about 3d printing lol.

No, Lego does not sell custom printed bricks in small quantities (I suspect if you wanted thousands of the same design it would be a different story).
To get your search to work you need to use the advanced features, specifically by removing results that contain 3D: print on ABS plastic -3D
That turns up mostly links on screen printing, which would be awfully fiddly to do with Lego pieces.
A friend has a printer that will print properly on Lego, but it was not cheap to buy. IIRC it's an inkjet that takes special cartridges, presumably using the same sort of ink that the screen printers use. If you're willing to spend a couple of thousand dollars on buying a printer I can ask him for details. My solution would be to pay him to print bricks for me, as I also prefer not to use stickers, but I rarely use decorated bricks so that hasn't yet been necessary.

There are many LEGO customizers who do custom printing, however please note that all printing makes sense only if hundreds of the same design are requested. Otherwise there is quite a bit of work involved with designing, formatting, color-matching and aligning each print. However if you have the money and willing to pay a few hundred bucks set-up fee for each design, there are options.
Please note that most LEGO customizers won't be willing to do exact replicas of LEGO's own design, as it is illegal to reproduce and sell them.
You might be better off getting water-slide decals, and even designing them yourself. The end result looks almost the same as direct printing on elements, although they will be more delicate.
If you are interested to get your own printer for LEGO pieces they are called pad-printing machines. They are expensive, but prices are coming down, especially on used ones.


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Retrobrite cleaning on old cellulose acetate bricks?
Is Retrobrite (cleaning with hydrogen peroxide, oxyclean, sunlight) effective or ineffective or, worse, downright destructive on old cellulose acetate bricks?
My understanding is that method of cleaning is designed for ABS bricks. What if there are cellulose acetate bricks mixed in the collection at random? Will they be harmed?

The yellowing that is common in some colors is caused when a fire retardant that was added to the ABS plastic breaks down under UV light.
One of the elements used in the fire retardant is bromine. When the chemical degrades, bromine atoms can be freed and can make their way to the surface of the brick where they bond with an oxygen molecule (O2) and take on a characteristic brown tint.
The Retrobrite process uses UV light to break the weak bond between the bromine and oxygen and then replaces the oxygen molecule with hydrogen (from the hydrogen peroxide solution). This molecule is colorless, so the brown tint disappears.
Cellulose acetate bricks did not contain the brominated fire retardant chemical and so are not susceptible to the yellowing problem. You will usually find that the older cellulose acetate bricks are brighter and hold their color more consistently than newer bricks that contained the retardant. Modern LEGO bricks no longer contain brominated chemicals.
Hydrogen peroxide can have a bleaching effect on cellulose acetate plastic. As with any bleach, prolonged exposure can damage materials. The solutions of hydrogen peroxide that are sold as household strength are relatively weak and should not significantly damage the plastic for the few hours they are normally in the retrobrite solution.


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How to Decipher Lego Building Instructions Filenames?
On the official site for downloading lego instructions, the filenames are often quite cryptic, and many sets have as many as six different files you can download and sometimes it's hard to tell which one you want. Can anyone enumerate what all those various part of the filename mean?
Examples 1:
Woody's Roundup! 7594

BI 3005/48 - - Download size: 5.71 Mb
BI 3005/48 - - Download size: 5.71 Mb
BI 3005/48 - 7594 V 110 2/2 - Download size: 5.94 Mb
BI 3005/60 - 7594 V 110 1/2 - Download size: 5.91 Mb
BI 3005/60 - 7594 V 140 1/2 - Download size: 5.91 Mb
BI 3005/60 - 7594 V 29 1/2 - Download size: 5.87 Mb
BI 3005/60 - 7594 V 39 1/2 - Download size: 5.87 Mb

Here's what I've figured out so far
BI = building instructins
3005 = set number
48 or 60 = ??
7594 = ??
V = version
110, 140, etc = ??
29 = A4 paper
39 = US letter paper
1/2 and 2/2 = the booklet number
Example 2:
Batman™: Arkham Asylum Breakout 10937
 BI 3016/12-65G - Download size: 4.68 Mb
 BI 3016/12-65G - Download size: 4.68 Mb
 BI 3016/68+4*- - Download size: 12.79 Mb
 BI 3016/68+4*- - Download size: 12.79 Mb
 BI 3016/76+4*- - Download size: 15.96 Mb
 BI 3016/76+4*- - Download size: 15.96 Mb
 BI 3016/80+4/65+115g - Download size: 14.5 Mb
 BI 3016/80+4/65+115g - Download size: 14.5 Mb

Now this one's even crazier 68+4* huh??
And it kind of looks like all the files are duplicated? Or is the second one possibly a newer or bugfixed version?

Apparently the number atfer the "/" (48,60...) seems to be the number of pages

Also, the page itself says:
Building instructions labeled "NA" or "V39" may be printed on US standard letter size paper (8½ in × 11 in, 215.9 mm × 279.4 mm).
Building instructions labeled "IN" or "V29" may be printed on EU standard A4 paper (210 mm × 297mm, 8.3 in × 11.7 in.)

Based on Jobarc's comment, it appears the numbers with plus signs between them after the slash, eg 68+4 (72) and 80+4 (84) are number of pages as well, though I'm not sure why in some cases they break out the numbers with an extra sheet (4 pages) separate

After emailing back and forth with LEGO, I think I have an acceptable answer:
Example:
BI 3005/48 - 7594 V 110 2/2 - Download size: 5.94 Mb
^   ^   ^      ^   ^     ^                   ^
1   2   3      4   5     6                   7

Stands for Building Instructions
A number for internal usage by different LEGO teams.

You'll see that many different sets share this number, and all the numbers are fairly close (generally in the early 3000's).  My guess is that it has something to do with whoever drafted and finalized the instruction manual.

This number shows the number of pages in the manual.

When the number is show x+y, that means x building pages, and y instructional pages (e.g. what to do with bricks, or what bags are needed).

This is the set number.
This number refers to the page format of the instruction manual.

V29 means ISO A4 paper format.
V39 means letter paper format.
Other Vs (like 110, 140, etc) are different file formats.  LEGO said "those are the types of versions throughout our country that we ship to".  I'm guessing that they are related to the official formats for the manuals that are included with the kits.

The booklet number:  x/y means x booklet number out of y booklets.
The file size of the instruction in megabytes (not megabits, as it would seem to imply).


text:
Unhappy minifig faces
I dislike how many current sets and mystery figures come with negative expressions such as sad, angry, and mad. Sure they have their place and purposes, but I'd prefer my son not have so many grumpy looking LEGO dudes--I liked the old "every minifig had a smiling face" styles better for that reason. Is there a cost-efficient way to get replacement minifig heads with more appropriate expressions? A way to provide feedback to the Lego group?

The classic minifig head can be purchased on Bricklink, and it isn't terribly expensive even in large quantities:
http://www.bricklink.com/catalogPG.asp?P=3626cp01&colorID=3
You can leave feedback on this issue via LEGO Customer Service.