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

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13
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4answers
346 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?
12
votes
2answers
1k views

Are Samsonite gears compatible with modern Technic gears?

Do the old Samsonite gears (above) work with current Technic gears (below) LEGO bricks tend to be backward compatible with older bricks, but since I don't own any Samsonite gears I cannot tell. ...
11
votes
1answer
281 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 ...
10
votes
1answer
320 views

What's the purpose of the clutch gear in Power Functions set?

I have just bought this set and wonder the purpose of the white gear in the middle: How can you use it in your Lego Technic projects? Is it available in other sets?
8
votes
3answers
3k 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 ...
6
votes
1answer
666 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, ...
5
votes
2answers
357 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 ...
5
votes
1answer
620 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 ...
4
votes
1answer
549 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 backward, the first gear does not move, but the second one does. I found ...
4
votes
2answers
385 views

What is the difference between 8T gears “Type 1” (3647) and “Type 2” (10928)?

On Bricklink I can see that there are two types of 8-toothed gear - a "Type 1" (3647) and a "Type 2" (10928). It's obvious these parts are not the same, but what is the functional difference ...
4
votes
1answer
357 views

Pre-Technic gears?

I have this set of LEGO gears. I remember seeing them first at my grandparents in the mid 80's. They predate my first Technic sets (~84 or 85). I have fond memories of my dad building a 3-speed ...
3
votes
1answer
110 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 ...
3
votes
2answers
2k 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 ...
3
votes
1answer
112 views

What does “No Friction” mean in Parts “Gear with 8 Teeth Wide, Notched and No Friction”

http://www.brickowl.com/catalog/lego-gear-with-8-teeth-wide-notched-and-no-friction-11955 As title, what does "No Friction" mean in the part "Gear with 8 Teeth Wide, Notched and No Friction" ?
3
votes
2answers
110 views

Gearing down a PF XL

I'm looking for the best way to gear down a Power Function XL. I need to achieve a very slow output RPM (less than 1-2 RPM). I've tried a 625:1 gear (trough 40:8 gear). Can someone link to a well ...
2
votes
2answers
76 views

How important is a center differential on a 4WD model?

I am looking to make a 4WD, single-engine powered vehicle, and I have seen others such as this which use three differentials to distribute the power to all 4 wheels: ...
2
votes
1answer
542 views

How to build a limited slip differential?

Lego provides a couple of ways for building a differential, such as this: and also provides a limited-slip gear like this: ...
2
votes
1answer
118 views

How much torque can a lego axle handle?

from to this question, it seems that the gears are stronger than the axles, which begs the question of how strong are the axles? if you connect one of the stronger motors, such as say the buggy motor: ...
2
votes
1answer
77 views

Which combination has a lower gear friction?

I need roughly a 1:3 reduction and I see a couple of ways to achieve it: using a 8t gear and a 24t gear (1:3) using 2x 12t gears and 2x 20t gears (1:2.779) using a 16t gear and a 40t gear (1:2.5) ...
2
votes
1answer
279 views

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 ...
1
vote
1answer
121 views

Parts/Step not fitting ( technic / gear not aligning)

working on Lego Technic; Recovery truck. Reached Step 27(book 1)....fixing the rope spool. and found that the white gear wheel is not fitting in. i.e., i have the white gear fixed on the shaft with ...
1
vote
1answer
62 views

Can you use a beveled gear as a pinion?

I would like to use the PF servo motor for steering, however it is very large - I was playing with the idea of having it mounted vertically, and then using bevel gears to change the direction of the ...