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Unread 02-23-2015, 12:52 PM
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FRC #0095 (The Grasshoppers)
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Re: Rivets vs threaded fasteners

We have used rivets in the past, but I don't really like them for four (engineering) reasons:

-There is a reliance on the human factor to install them, which requires training. They can't be 're-set' like a riv-nut can be.
-Holes cannot be opened up as much to allow for mis-alignments or tolerance stack-up when using rivets.
-They are (as pointed out) sometimes tricky to use with soft materials or materials susceptible to creep.
- Drilling rivets out takes a power tool, a drill bit, and can introduce metal swarf into a robot. Not an ideal situation for several reasons.

Rivets can, and are, used quite successfully in FRC. I prefer the advantages of threaded fasteners and blind threads to those of rivets though.

We use PEM (cinch) nuts and Riv-Nuts frequently on our robot. We love blind fasteners because assembly is faster than a fastener+nut and we can put mounting points in locations traditionally unavailable to faster+nut combos. We can put blind threads into thin material and thick materials with ease. Everything can be quickly disassembled. And, unlike tapping material directly, damaged threads can easily and quickly be replaced. At least as quickly as rivets.

Also, I would posit that I could uninstall and then install a blind-threaded fastener faster than a rivet of similar strength could be removed and installed. Cordless impact drivers are *awesome*.

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