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Questions tagged [gears]

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

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3 votes
1 answer
127 views

Create a gimbal like structure with Technic gears

I would like to attach a sensor to a plate, and tilt that plate slightly in the XY direction respectively, without moving the plate itself. Similar to this (force feedback joystick concept) like this ...
2 votes
1 answer
65 views

Full contents list of Lego gears boxed set 802 (unknown year) [duplicate]

Is there a definitive complete list of what should be inside one of these boxed sets? In particular, pins, rods/axles, bricks, clips, and other general accessories (including their quantities)? I ...
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 ...
6 votes
2 answers
2k views

Error correction after building the D11

I just finished the D11 bulldozer. The last LEGO set I built was 55 years ago, now I got this big machine and I really enjoy it! But I have troubles with the the calibration and I think the failure is ...
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 ...
3 votes
1 answer
152 views

Lego 42082 Rough Terrain Crane superstructure does not rotate easily when master selector is set to neutral

My son has been building the Lego 42082 crane and is on bag 9. I don't believe the central section is functioning properly as I believe the rings should turn much more easily by hand than ours does. ...
2 votes
2 answers
172 views

Alternative to LEGO Education for Technic parts?

I am trying to work through the LEGO Education platform, however am stuck at where to buy a big set of gears and similar from. There are sets of 50pcs for $40+, which is clearly a ripoff. Or 500 ...
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 ...
9 votes
3 answers
350 views

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

This piece was in with all of set 76911's spare pieces in a separate bag. 76911 is the only Speed Champions set I have so I don't know if the piece comes in any others. I looked at the inventory for ...
6 votes
2 answers
536 views

How can I connect a 4mm Stepper motor shaft to a technic gear?

How can I connect a 4mm or 6mm stepper motor D shaft to an old Technic gear? I would like to mount an old 8-tooth gear to a 4-6 mm diameter stepper motor shaft. Lego part: 3647: Stepper motor: ...
2 votes
0 answers
107 views

Fit motor to old tractor

I'd like to motorise this tractor I built from an old Lego book. I've 4.5 volt motors. The model is 6 studs wide, the motor is only 4, and since the tractor uses big wheels it would be too fast. Is ...
3 votes
1 answer
538 views

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

I’m not sure if the gearbox is supposed to move when it’s in neutral but the gearbox only moves when it’s in drive or rear. If I made an error can someone please tell me if there is a way to fix it?
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, ...
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.
-2 votes
3 answers
302 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?
5 votes
0 answers
804 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 ...
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 ...
3 votes
1 answer
176 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 ...
2 votes
2 answers
181 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?
4 votes
1 answer
450 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/...
4 votes
3 answers
492 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 ...
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 ...
9 votes
1 answer
2k 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 ...
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 ...
6 votes
2 answers
946 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 ...
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 ...
3 votes
2 answers
2k 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. ...
2 votes
1 answer
437 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 ...
0 votes
0 answers
186 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....
14 votes
1 answer
1k 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....
8 votes
2 answers
4k 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-...
3 votes
2 answers
455 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?
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 ...
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 ...
4 votes
2 answers
816 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 ...
4 votes
1 answer
274 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 ...
0 votes
0 answers
176 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 ...
10 votes
4 answers
2k 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 ...
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 ...
10 votes
1 answer
514 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 ...
5 votes
1 answer
545 views

Does LEGO Digital Designer include part 4539880?

Does anyone know if LEGO Digital Designer includes the part 4539880 (often used for housing differentials) ?
7 votes
2 answers
243 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 ...
3 votes
1 answer
290 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 ...
12 votes
1 answer
22k 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 ...
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!
5 votes
2 answers
3k 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 ...
1 vote
1 answer
775 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 ...
3 votes
1 answer
176 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 ...
7 votes
2 answers
532 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, ...
2 votes
3 answers
571 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.