[Dan Richardson]

We used 1/4 this year a step up from 3/16 and 1/8" rivets. We seemed to cut the amount of rivets we used in half this year by just switching to 1/4" They are gods (small g) among meer mortals in the fastener kingdom. But there are a few criterion that I like to follow when using them.

First, the ultimate importante is to have a pneumatic riveter, its much nicer/cleaner if you do and your kids don't end up walking around like popeye with one massive fore arm. Make sure you buy the right size riveter, and you get what you pay for. This year we used harbor freight riveter ran us around $95 but we had some issues, worked out the kinks and got it going pretty well. Don't waste your time with the HF hand riveter, it literally broke on the second rivet we popped.

For 1/4" aluminum is good, don't really need steel, we popped a few in the highest stress parts of our bot, but ehh it was probably overkill.

If you use 1/4" make sure you have plenty available, they are somewhat hard to find at a local hardware stores, we tried somewhere in the neighborhood of 6-10 stores before we tracked them down. Order them with the other parts, its cheaper and easier. ( I just happend to mis count )

When drilling out rivets be careful, this is kind of why I cringed when Paul said the challenge. Its true, rivets can stack up speed wise with most of FIRST style bolt construction, but hopefully you really won't have to drill out most rivets. Often times when drilling them out, you can open the hole a bit more, if you do this overtime the rivets aren't as snug... I know its like a few thousandths thing each time but if you come in at an angle I just hope your safety factors are high. Which with rivets, they usually are higher than you even know.

Use them everywhere and anywhere, sheet metal construction is one of the strongest available options if you want to put the engineering into it. One of the greatest parts is its amazingly cheap, to cut out entire robots worth of sheet on a water jet it can be a couple hundred dollars worth of labor. When all you have to do is place shafts and pop some rivets, its an amazing building experience.

If you don't for some reason think the rivets are strong enough, there is also the rivet/apoxy route. Adding structural apoxy like loctite E-20NS or the E-20HP which IF YOU NEVER WANT TO TAKE IT APART is amazingly strong.

So what have I learned with rivets over the last two years,

strong as heck, easy to use, have a good pneumatic riveter, apoxies are awesome if you don't want to take it apart, rivet where possible, don't drill them out too often, marvel at how cool they look and how light they are. Play count the rivet games with other teams that come by.

Happy Riveting.