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Questions tagged [gears]

Gears transmit rotary motion and are commonly found in Technic sets.

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8 votes
1 answer
3k views

Any tips for aligning gears in LDD?

I'm trying to create the 42052 (Heavy Lift Helicopter), and other Technic sets. Aligning gears' teeth is relatively difficult, and the 'Hinge Align' tool rarely works. Please help!
LenTheSpaceWolf's user avatar
8 votes
1 answer
8k views

What is the "Module" of a LEGO gear?

Module, m this indicates the tooth size and is the number of mm of pitch circle diameter (p.c.d.) per tooth. For gears to mesh, their modules must be equal. Gear ISO standards and design methods ...
user2813274's user avatar
  • 1,156
6 votes
1 answer
3k views

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

The directions show the gears are suppose to move counter clockwise. When I follow the directions on page 268-269, and push the reverse button on the Lego power-up app for the Grand Piano, the gears ...
David Sparks's user avatar
4 votes
1 answer
2k views

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

I am building the D11 dozer and some of the tests like 2 and 4 are moving the parts in the opposite direction that they are supposed to be going. I took apart the entire build and rebuilt it and the ...
Aidan's user avatar
  • 41
3 votes
1 answer
539 views

Technic Rough Terrain Crane (42082) doesn't move

After first book, crane won't roll if pushed. If this normal. I know when you free soon one wheel, the other will go opposite direction, but when I try to spin all four in one direction, it locks. It ...
Joe Stetson's user avatar
17 votes
1 answer
3k views

How can I make a precise one-way clutch using Technic elements?

I need a mechanism so that if a (NXT) motor rotates forward, it moves one gear, but the other stays still, but if it rotates backwards, the first gear does not move, but the second one does. I found ...
Ari Porad's user avatar
  • 273
16 votes
4 answers
556 views

How can I fix a flattened gear?

I have an old small gear that somehow got flattened to an oval shape. The axle hole is too narrow to slide a bar through, although it is not completely closed shut. How can I repair this gear?
Pubby's user avatar
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14 votes
1 answer
1k views

What is the difference between these hole shapes?

I purchased an assorted bag of LEGO Technic pieces. There are pieces with axle holes, but what puzzles me is that the holes are different from what I am familiar with. There's a piece with an ...
Torben Gundtofte-Bruun's user avatar
13 votes
4 answers
2k views

2:1 gear ratio in stud-less Lego Technic

Is there a recognised technique to create a 2:1 gear ratio in stud-less Lego Technic? Neither of the two methods suggested here (studded though) work. 24T/12T with a 2L x 1L axle offset does rotate, ...
Peregrine's user avatar
  • 433
12 votes
4 answers
10k views

How to make a conveyor belt with LEGO parts?

I am making a small robot with an Arduino and Technic LEGO powered by stepper motors. I am planning on moving small rocks throughout my machine. Does anyone have an idea of what kind of Technic LEGO ...
bogen's user avatar
  • 825
11 votes
3 answers
4k views

What are the torque limits of gears?

I am using Lego in the classroom to introduce students to geared machines. As part of this I am asking them to design a winch, using a small 1.5V DC motor and a collection of the common Lego gears, i....
Li-aung Yip's user avatar
10 votes
1 answer
9k views

9398 4x4 Crawler front wheels rotate in the opposite direction to the rear wheel

We've just finished 9398 4x4 Crawler. Everything looks good, the motors work but the front wheels rotate in the opposite direction to the rear wheels, they also turn in opposite directions. What could ...
Belle's user avatar
  • 103
9 votes
1 answer
2k views

Strongest gear configuration

I'm building a (what I hope to be) high-speed car using two PF-XL motors together and some gearing up. However, there's a point where I have to rotate the axle with power (that comes from the 3 speed ...
Alex's user avatar
  • 191
8 votes
2 answers
16k views

How can I transmit horizontal torque to vertical?

I have a setup where I have a step motor which I am attaching a gear onto. The motor will make the gear stand horizontal in a small vehicle. Is there any good gear combinations of LEGO gears that can ...
bogen's user avatar
  • 825
8 votes
2 answers
1k views

Any way to create a gear+chain, like for a bike?

I would like to create a LEGO bike. I can imagine how most of it would work, but i'm stuck at the chain. I need a way for the turning pedals (at one spot) to cause the wheel (in the back) to spin ...
Scimonster's user avatar