[robz71lm7]

So a certain student's machine design professor has pushed the idea into people's heads that we should use SAE Grade 5.2 or greater for all thing structural or important. Good luck finding those bolts, I knew they existed, but have never seen any. His logic is that the yield strength of a grade 5 bolt changes when you get over a certain diameter (1" IIRC) whereas the 5.2 grade's yield strength is constant. We also had a machine design project where we had to specify a size and preload for a grade 7 bolt. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/rolleyes.gif) Also according to him, nobody makes bolts with cut threads any more. Aren't most cheap chinese bolts manufactured with cut threads?

[pknowles]

Aren't most cheap chinese bolts manufactured with cut threads?

I thought most hardware had cut threads, but you can always get stronger rolled threads if you order them. I always thought the stuff you find in the hardware store is cut threads, because cut threads are a hair cheaper.

This post has been edited by pknowles: Dec 7 2005, 01:40 PM