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19 votes

How can I place a motor in the middle of a Technic beam with an odd number of holes?

I'd address this with bevel gears:
Michael Verschaeve's user avatar
18 votes
Accepted

How can I place a motor in the middle of a Technic beam with an odd number of holes?

Something like this would work. Since this is just an idea pictured assembly doesn't feature any bracing required for this solution to work properly. Another thing to mention - 8T gears doesn't like ...
Alex's user avatar
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15 votes
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Part identification: 40 tooth gear from The LEGO Movie

From this image, you can count the teeth well enough to determine there are actually 60 teeth, not 40: This does not appear to be a real part. It also appears you aren't the first to notice this. ...
Alexander O'Mara's user avatar
15 votes
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What's this round blue gear piece from set 76911?

This is a blue Non-Vented Double Dead-Ender Cap (or a variation thereof), also called a Luer taper/lock, sold by various OEM suppliers. According to the supplier KempCo Specialties, these are multi-...
Tuzi's user avatar
  • 788
13 votes
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What is the purpose of the 8 tooth timing gear?

When looking at Blakbird's Technicopedia page for this Technic set, this part is indeed used as a rotary encoder in combination with the bar code scanner. See the last entry on the page.
Joost's user avatar
  • 8,053
13 votes

What's this round blue gear piece from set 76911?

Ok everyone, I have a disappointing update but it does answer my question. I didn't actually get round to contacting Lego about this because I mentioned my discoververy to my mum first. She ...
Toomany Bees's user avatar
12 votes
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What are the dimensions of a technic axle?

I found CAD files for LEGO technic axles here: https://grabcad.com/library/lego-technic-axles-1 and some gears which have holes for technic axles here: https://grabcad.com/library/lego-technic-gears-1 ...
Josh King's user avatar
  • 1,911
11 votes

Grand piano page 269 of instructions - are the gears suppose to stop after a quarter turn or keep going when reversing directions

Tl;dr - Your piano appears to be functioning correctly. The step you mention appears to be resetting the gear to a known position. The playback direction is clockwise and free of restriction. The ...
D M's user avatar
  • 959
10 votes
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9398 4x4 Crawler front wheels rotate in the opposite direction to the rear wheel

Likely you'll have the differential gears oriented wrong in the front or back section. The differential gear is this piece: Please check the instructions carefully and see if the orientation of ...
Michael Verschaeve's user avatar
9 votes

2:1 gear ratio in stud-less Lego Technic

I felt my original answer got messy. The simplest answer is that you already had it. I experimented with variations of your 12T/24T build and experienced varying degrees of the stiffness you ...
JohnnyB's user avatar
  • 3,274
9 votes

2:1 gear ratio in stud-less Lego Technic

Here's a solution I found in Yoshihito Isogawa's LEGO Power Functions Idea Book Vol. 1 - Machines and Mechanisms: EDIT based on Eric's comment: And here's using the black piece from JohnnyB's tweak:
Uli's user avatar
  • 2,548
9 votes
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How can I assemble 2 opposing gears so that the axle rotations are perfectly parallel?

How can I get 2 opposing gear's axles to be perfectly parallel? Are there any good workarounds? You could use an idler gear. It will even out the offset. Yet, at the same time, it (or any odd ...
Uli's user avatar
  • 2,548
8 votes

Why does this "useless machine" use out of production parts?

Because the builder had those parts, and knew how to use them. Perhaps those parts weren't out of production when that was build. There are extremely few MOC's that are updated when the parts go out ...
Henrik supports the community's user avatar
8 votes
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Error correction after building the D11

I made a major rebuild of the D11, opened the gearbox, and found this orange Changeover Rotary Catch in a false position on Step 110 (Page 107) of the instructions. After the correction, the D11 runs ...
Jeeplego's user avatar
  • 141
7 votes

How can I assemble 2 opposing gears so that the axle rotations are perfectly parallel?

If you use a crown gear or bevel gear to connect your gears twice perpendicularly, they are exactly opposing each other, turn in opposite directions, and are parallel (if the respective axle is ...
Wrzlprmft's user avatar
  • 2,174
7 votes

Insert a gear into a turntable?

I'm struggling to understand why would there be a need to insert 24T gear inside turntable gear. If you need rigid connection - it is best to use existing attachment points for you assembly. Internal ...
Alex's user avatar
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7 votes
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Insert a gear into a turntable?

Indeed I had to disassemble it (which went without much effort) but the 24 tooth fits fine: It can slip up or down for about half a stud but is stuck otherwise.
Michael Verschaeve's user avatar
7 votes
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Why does this "useless machine" use out of production parts?

There is no universal LEGO Technic set that contain each and every gear LEGO has ever produced. None1 of those elements are out of production. You may not acquire all of them in a single set, yes, but ...
Alex's user avatar
  • 23.2k
7 votes

I am building the LEGO 42131 D11 dozer and some of the parts are moving in reverse when testing

I had the same problem but turns out the app graphics are just wrong. Completed the build and it works perfectly fine.
Tom Wilson's user avatar
6 votes

High Torque Subtractors

It sounds like you need a stronger differential. Might I suggest this design by Nazgarot: If you make two, you can build a big and sturdy subtractor like this (probably customizing the gear ratios ...
Alexander O'Mara's user avatar
6 votes

Does LEGO Digital Designer include part 4539880?

Yes, but only one color choice of light bluish gray is available in the default mode.
Rin Rio-Oki's user avatar
  • 8,893
5 votes
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Which system is more efficient?

The torque in both versions would be the same. Your first version just adds 3 of these gears: The ratio between them is 1:1 so it will be the same as if you connect the axle straight into those ...
Alexander O'Mara's user avatar
5 votes

Technic Rough Terrain Crane (42082) doesn't move

Motor is only being used to operate the crane, not to drive the model. So driving/pushing shouldn't be blocked at any time. I suspect there will be an issue with position of differential - if placed ...
Alex's user avatar
  • 23.2k
5 votes

Gearbox doesn’t move when it’s in neutral - Is that normal?

The point of the neutral position in a gearbox is that it disconnects the engine from the drivetrain. Therefore no movement is expected at the wheels when the engine turns and vica versa. If the ...
zovits's user avatar
  • 16.8k
5 votes
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Create a gimbal like structure with Technic gears

Check out the instructions (around steps 10-11) of 8855 Prop Plane. This model has a control stick that can tilt around two perpendicular axles:
zovits's user avatar
  • 16.8k
4 votes
Accepted

Can you use a beveled gear as a pinion?

Seeing a picture of your progress would help tremendously. The way the question is worded, it sounds like you were wanting to drive the beveled gear directly from the servo to the rack at a 90 degree ...
JohnnyB's user avatar
  • 3,274
4 votes

Any tips for aligning gears in LDD?

Use math. Here is a simple example... Suppose we want to line up two 8 tooth gears. Start by placing two axles and one of the gears... Since there are 8 teeth on the gear, we can figure out that the ...
David Lechner's user avatar
4 votes

How do I increase axle speed using gears

You can't do this with the gears you've listed, but I'm not sure that you've listed the proper gears. I don’t believe that 32 or 64 tooth gears exist. I at least don't have any. You can do this by ...
jncraton's user avatar
  • 40.7k
4 votes
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Lego Digital Designer: Having Gears Interact with Toothed Bar

The LEGO Digital Designer software does not have the ability to simulate the interaction of gears. There is a similar software program called SR 3D Builder that does have this capability.
David Lechner's user avatar
4 votes

Lego Digital Designer: Having Gears Interact with Toothed Bar

LDD is a design solution for static models. It is not a functional simulation tool. The gears turn with the crank handle if they are associated to the same group, but that is only because the gears, ...
Phil B.'s user avatar
  • 16.9k

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