# Chains and gears--fitting together, any advice?

I’m trying to build a tank track (for a robot, and things are coming together pretty nicely.

I’m having a huge problem trying to line up gear teeth and a chainlink. Most tanks seem to have gears in the corner of a track so they’ll bite into two points of the chain.

This is driving me nuts.

Are there any tutorials? Bits of advice? Math? I tried actually googling for, unrelated to blender, the math of gear and chainlinks but couldn’t find an answer and wouldn’t actually know how to apply it properly anyway (most likely).

The gear here looks obnoxious, just me playing around with different things, trying.

I hope this is the right subforum to ask this sort of thing in.

Thanks.

There are a number of tank tread tutorials specific to blender online.

Find out how many chain links correspond to the number of gear teeth for a single revolution. After that you can make a driver that takes the gear’s rotation on that axis and advances the chain forward with that exact length every 360 degrees.

As for the math, you can imagine a gear completely wrapped around the chain so that it covers all 360 degrees - the correct length is that circle’s perimeter, which should be π * (the diameter of the gear + 2 * chain height).

Thanks Pesho.

Sterling, I’ve looked at several tutorials and most were merely concerned with developing a track that fit a curve, and didn’t talk about much else. I’ve seen sims of gears in tank tracks and chains styled like the chain in my image, but I didn’t find any that actually discussed proper gear sizing.

I’m trying a few different things already, and will consider what Pesho said as well.