Quote:
Originally Posted by Gdeaver
Our team used the rivets mentioned last year on the kit bot frame. They held up well and my subjective feeling is that it was a little stiffer.
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I'll ask, since nobody else has; what kind of rivets were you using in the frame?
I shopped around Grainger (since there's a warehouse here in town) and found a few potential options:
5LE49 - 1270 shear/830 tensile, $8.86/25. (Aluminum w/ aluminum mandrel)
5LE56 - 2400 shear/1850 tensile, $10.40/10. (stainless/stainless)
5LE53 - 2400 shear/1850 tensile, $7.45/25. (steel/steel)
4AR31 - 1270 shear/1550 tensile, $7.01/100. (steel/steel)
The hitch with 4AR31 is that the material thickness only goes up to 0.250". While that's on the money for the kit frame (in theory, since you're joining two 1/8" pieces of metal next to each other), it would seem like going to ones with 3/8" grip range (which all the rest are) would give us a bit of breathing room.
No small part of my motivation to try rivets stems from what Kevin noted: it's a pain in the butt to get to some of those nuts, particularly once you've got the rest of a robot on board. It became the job of one of the kids at each event to check each nut and bolt and tighten as necessary, and Ron Karpinski still handed me a fistful of nuts and bolts at BE.
Greg Needel was talking with me the other night on the subject, and he was a little wary of going all rivets. He threw in the idea of leaving one bolt in on each end of the connections to soak up some of the shear loads. While I'd still take zero bolts over non-zero bolts if it does the job, checking 12 or so bolts sure seems a lot easier than checking the (if I counted right) 72 on a standard kitbot.
1618 is getting the riveter Don linked to, though the team is currently on a Thanksgiving hiatus until the 28th. I'm hoping we can get some knowledge before the holidays, or at least before Kickoff.