Keeping Chassis “Square”

Aloha all,

Looking for any tips and tricks you have for keeping your chassis “square”. We normally build “H” chassis and always run into the issue of the rails not being perfectly aligned.



Shoulder screws are really helpful for keeping things square.


Check out @Xenon27 quality drives. there are plenty of things you can pull from them.


“Cading” your chassis before actually building it can help you align everything by helping you plan your chassis out and adjust anything misaligned, so you will know where to connect every part to the rest of the chassis (when actually building your chassis) for it to be aligned how you want it to be.

If you don’t already have a CAD software, reading through this topic will help you find one:


Oddly building with an adjustable square is the way to go. Most school desks / benches are flat enough to use as a measuring plate.

Using 3 screws in each corner is also a way to keep things that way.


-Make sure you have 2 points of support for all shafts.
-You need at least 2 cross-braces, and at least one needs to run all the way across all 4 drive channels.
-Braces should be as far apart as possible.
-braces on the bottom are structurally stronger than those on the top, but you should do both if possible.
-you should connect the ends of the drive channels with standoffs or 1x1 angles to leep those square.
That’s most of it, everything else has already been mentioned.


Not quite: remember the “whole number ratio” right triangles, 3-4-5 (and 6-8-10, 9-12-15, etc), which give you the hole lengths/hole spacings for diagonal bracing.


Don’t forget the 5-12-13 right triangle…

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I’ve used the square posts on the hex nut holders to align the metal straight, as well as shoulder screws, but you can eyeball it as well. Honestly, as long as everything spins freely it doesn’t matter how straight the drive is. I’ve had drives that I’ve used force to bend the sides to go straight.

Are you competing this year?


Thanks everyone for the responses! All of your tips are very helpful!

Yes we are thankfully. We are stoked to be back!

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