[Jon Stratis]

The one real nice thing about stainless steel bolts, is the need to never replace them (in a properly designed usage). Aluminum simply isn't as durable, and as already said, it's pretty easy for a student to over tighten and pop the head off. All of our bolts are stainless steel.

That said, the key to any good design is using the right part in the right application. Some things on a robot (like the frame that provides the structure for the entire robot and takes the brunt of the impacts) should be done with 14/20's. Others can be done with 10-32's. Still other applications can use smaller sizes.

We have a standardized set of bolts for use with our robot, everything from 1/4-20's to 4-40's. by using a constant thread count for each size, we can match up bolts or taps very easy - there are no 10-24's in our shop, so we have no 10-24 nuts and no 10-24 taps. All we have is the equipment for 10-32's.

We also use pop rivets for a lot of applications. By a lot, I mean most applications that aren't structural. A couple of pop rivets can, in the correct application, easily replace a heavier bolt.