[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?

[severous01]

i'v seen the 3 tick bolts. i had to replace the tranny on the POS honda and the tranny bolts were those. they were cut threads.

from what i learned at the lumber yard when i was younger is: all bolts and screws are made round, with the heads still on, and no threads. then they are shaped and sized down, then the threads are cut last.

about the rolled threads...i have no clue. never even heard of them