Chassis Materials

Hi, our team is planning on making chassis out of C channels. Our tank drive will probably be similar to an ITZ robot with an H drive. The question is, would it be better to use Aluminium or Steel? Last year, we used Aluminium but the chassis bent a little. That might not be because of the materials. But can you list the Pros and Cons of both Aluminium chassis and Steel Chassis?

I still think aluminum is so much better. if you reinforce it enough, it wont bend unless under immense stress, its way lighter, and probably easier to park with.

^ agreed, imo steel is way too heavy its benefits are outweighed. Just make sure your aluminium base is reinforced at multiple points (having extra c-channels across the left and right segmants help quite abit). It also helps to ensure the tower is well-braced to multiple points on the base to distribute weight more evenly and avoid warping the c-channel it’s mounted to.

There’s very few scenarios in which steel is going to be better than aluminum as far as vex goes. Our general chassis structure is always 6x 17.5" Aluminum C-Channels: 4 along the robots length to house the wheels, and then two across to mount other systems to, prevent warping, and bring the whole robot together. It is also convenient that there’s 6x C-Channels to a pack.

My recommendation would be to make sure you have C-Channels going the entire width of your chassis and to give any lift mounts a strong triangle support so all the load doesn’t get transferred through the attachment point.

I’m trying to figure out how to word this without drawing a picture lol, but it is also very important that you have the thicker side of the C-Channel running vertically. A 1x2x1 C-Channel will be more resistant to bending along that 2 Hole side because it is thicker, so you’d want to orient it so that the thick side is facing to the side, and thus trying to lift either side of the chassis (and bend it) would be putting stress through that thicker part of the Channel. That will make it less prone to warping.

That has been my standard chassis design for the last few years and we’ve implemented it on probably 30+ #400 robots to great success! Our robots have been almost entirely aluminum in structure and using Steel in Vex is almost never the solution in my experience.

Best of luck!