Quote:
Originally Posted by bardd
Do you ever tap wood or plastic? Or is that the wrong way to go?
Also, what tools do you use to tap? I don't know any, I'm afraid to say...
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There are PEM fasteners for plastic, but I've never used them. Google "PEM nut" and you'll find Penn Engineering's website. There's more info there. Tapping it directly is possible, but it's also weak. For example, there are nylon nuts and bolts available...but those are often for electronics applications. I have heard of them being used in FRC as a weak fastener that's designed to fail in shear, to protect more expensive parts of a manipulator.
If you need metal threads in wood, use a Tee Nut (yes, there's like 8 different meanings to the term). The type you'll want is something like McMaster 90975A053. The center of that nut is threaded for the bolt, and the prongs dig into the wood.
If you do use Tee Nuts in wood, make sure you press them in and then hand tighten a cap screw/washer combination into it to get the prongs to set properly. Otherwise, you risk spinning the nut and gauging the wood. Also, a judicious application of polyurethane glue (like Gorilla Glue) really does a lot to improve the confidence of the connection.