Questions tagged [gears]

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

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16 votes
2 answers
2k views

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

Can you give me some advice how to make it so motor will be in the middle, but at the same time keep the functionality of the 2 axles on the sides? It can go further up if necessary.
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  • 163
-1 votes
3 answers
242 views

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

I found this new video. It uses out-of-production parts like the transmission parts. So when I tried to buy these elements in new Technic sets, I didn't find some of them. Any suggestions please?
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  • 194
0 votes
0 answers
39 views

I can't build gear on Digital Desinger [duplicate]

I'm new to this program and I can't put a gear in place. I'm trying to build a worm gear but it doesn't work.
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5 votes
1 answer
442 views

LEGO Bugatti Issues

This is my first post and my first LEGO set. I recently built LEGO Bugatti Chiron with all the features working. I am however having an issue with the rear axle/wheels. The rear brake calipers fall ...
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8 votes
2 answers
2k views

Insert a gear into a turntable?

Is there a way to insert a 24 tooth gear into a turntable of the 48452cx1 type? --> Is there any model to feature any tooth gear (even smaller) used inside this turntable? This specific ...
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  • 503
3 votes
1 answer
140 views

Gearing problem

I have a technic MOC with lots of gears which runs fine when motorized with the Control+ L motor, the motor itself attached to the "dumb" battery box that would have been included with the ...
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5 votes
1 answer
996 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 ...
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2 votes
2 answers
163 views

Automating rotation of a block on a track

How do I rotate a block 180 degrees after an item (like a car or train) passes a certain point in a track?
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4 votes
3 answers
328 views

Extra Pieces for Lego Gadgets Book

My son is having a lot of fun with the Lego Gadget set (book and bricks), but he can only build one thing at a time, and would love to have a lot more of the types of Lego bricks that came with the ...
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4 votes
1 answer
230 views

How would one parametrically create a LEGO-compatible gear?

If a gear was intended to smoothly mesh with standard LEGO gears, how should it be defined? While I know that the mean diameter (average of inner and outer diameters) of a LEGO gear should be 1mm/...
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3 votes
1 answer
293 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 ...
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8 votes
1 answer
1k views

What is the purpose of the 8 tooth timing gear?

I recently ran across the 32060 Technic Gear Timing Wheel 8 Tooth element when sorting a mixed bag of parts. This element doesn't appear in many sets as a functional element. Here's one example from ...
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3 votes
2 answers
1k views

How can I make my LEGO engine go faster

I have a LEGO engine powered by a PF XL motor but I didn't realize until now that the motor is not that fast and that even when I increase gear ratio the gears always get either unattached or jammed. ...
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  • 439
6 votes
2 answers
574 views

How much energy do LEGO Technic gears lose to friction?

So, I recently watched a video by the Brick Experiment Channel about building a 1 Googol:1 reduction gearbox, which at the time of writing this question, is at #44 on Youtube Trending. At the end of ...
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0 votes
0 answers
117 views

Front driveshafts on landrover defender don't stay in place

The front driveshafts on my Land Rover Defender keep falling out, then the cogs fall out of the front differential. I have done them three times as per the manual, but every time I get the same result....
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2 votes
1 answer
304 views

How to make a Lego continuous conveyor belt

So I need to make a continuously working conveyor belt transporting blocks. I have seen this post, but additionally, as already said, I have to make it work continuously transporting blocks,so I have ...
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12 votes
4 answers
1k 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, ...
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  • 423
3 votes
2 answers
355 views

Lego Technic 60C01 Clutch Gear Bore size

I was wondering what the bore size is off the 60C01 clutch gear as I was unable to find it anywhere. Also, what is the pitch of such gear?
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  • 29
4 votes
1 answer
229 views

How to debug gears in the Bucket Wheel Excavator?

My 8 year old is just finishing the Bucket Wheel Excavator. He turned the motor on and there is a significant clicking noise. It looks as though the top gear noted in the picture gets stuck. Not sure ...
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0 votes
0 answers
138 views

Is there any software except SR 3D Builder with the ability to simulate the interaction of gears that doesn't require scripting?

I'm aware that one can do that in LDCad but with scripting. Should I invest my time in learning SR 3D Builder or is there any other option? It's just not a very intuitive software for me but I might ...
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10 votes
1 answer
7k 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 ...
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10 votes
4 answers
1k views

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

Due to the way all the modern LEGO gears are perfectly quarter-turn symmetrical, there doesn't appear to be any way to assembly 2 opposing gears such that I get a 2 perfectly parallel axles. This ...
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14 votes
1 answer
976 views

Part identification: 40 tooth gear from The LEGO Movie

While watching clip of the LEGO Movie, I found a strange part: Slightly earlier in the video, its part number is shown as 3649. But it doesn't match the 40t gear I know nor the pictures on bricklink....
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5 votes
1 answer
519 views

Does LEGO Digital Designer include part 4539880?

Does anyone know if LEGO Digital Designer includes the part 4539880 (often used for housing differentials) ?
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  • 51
7 votes
2 answers
225 views

9398 reduction change

I am studying implementation of 9398 crawler reduction. Here is the stripped part, in order to see the gears and their relation - the image is made with the excellent tool which is LDCad. My idea is ...
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  • 503
10 votes
1 answer
390 views

High Torque Subtractors

I would like to use a subtractor in my next RC LEGO tank, as it enables the vehicle to turn on the move, as opposed to stopping and then turning. Unfortunately, the subtractors I have tested so far ...
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11 votes
1 answer
14k views

What are the dimensions of a technic axle?

I'm working on a LEGO compatible motor system that will be largely 3D printed. I want the connectors to fit standard LEGO axles, but I haven't been able to find the dimensions online, and I don't ...
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5 votes
2 answers
2k views

How to best transfer power at 90 degrees for high torque applications

So, I am building a tank model and this is the transmission I have been working on: Description: There are two gear pairs for gearing up (16t to 8t gears) and one gear pair for gearing down (worm ...
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3 votes
1 answer
219 views

Clutch gear test

I have two white 24t clutch gears, one marked as 2.5-5Ncm and another unmarked - how can I assembled them in a way to test which one "gives" first ) i.e. has torque before it slips - I was thinking to ...
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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!
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1 vote
1 answer
713 views

How can I build a compact EV3 gearbox?

I'm building a sumo bot in EV3 and would like to have both 1:1 and 1:3 gear ratios, with the first being useful for general driving and the second more for pushing other robots. My problem is, I ...
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3 votes
1 answer
169 views

Which system is more efficient?

I got a few XL power functions motors, and want to combine them to make a racing car. Let's get to right to the question: Which one save the most torque power? This one... ...or this one? PS: It ...
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2 votes
3 answers
522 views

How do I increase axle speed using gears

How do I increase speed of my output axle 24 times using 8, 16, 32, and 64 tooth gears using LEGO Mindstorms components? I checked Sariel's website but it was no help.
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5 votes
2 answers
5k views

Lego Digital Designer: Having Gears Interact with Toothed Bar

I just started using LDD, and I have been trying out a few things that I couldn't do with the limitations of my Lego collection. One thing that has me caught up is that I can't seem to get the ...
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7 votes
2 answers
469 views

Non-working technic system

Recently I've been working on a car which when going forward is fast, and when going backward automatically goes slowly. Here are two photos of it: (Just replace the text by "input") As you can see, ...
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4 votes
1 answer
432 views

Are DUPLO gears compatible with LEGO gears?

Can I make a transmission from DUPLO gear (Early Simple Machines Set 9656) to regular-sized gear?
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  • 143
3 votes
1 answer
404 views

How to Motorize the LEGO Mars Rover

I am looking for some suggestions. My daughter is building the Mars Rover set (go here for the details: http://www.eurobricks.com/forum/index.php?showtopic=98222) for a presentation at school and I ...
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4 votes
1 answer
475 views

Any issues with this non-standard gear combination of 12t gears?

I don't see any "accepted" gear ratios for a stud-less direct-diagonal gear combination on sariel's excellent gear coupler but by shifting 12t gears such that they mesh off-center, it seems to work (...
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  • 1,146
6 votes
1 answer
601 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) ...
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  • 1,146
8 votes
1 answer
6k 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 ...
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5 votes
2 answers
5k 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: http://www.eurobricks.com/forum/...
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  • 1,146
4 votes
2 answers
659 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 ...
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  • 1,146
7 votes
2 answers
2k 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: ...
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  • 1,146
8 votes
2 answers
3k 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: http://www.brickowl.com/catalog/lego-technic-differential-with-one-gear-28-...
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  • 1,146
3 votes
1 answer
412 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" ?
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2 votes
1 answer
582 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 ...
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  • 141
6 votes
2 answers
807 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 ...
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  • 61
8 votes
2 answers
959 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 ...
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13 votes
1 answer
3k 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?
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14 votes
1 answer
907 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 ...
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