Logo
FULL SITE MENU

Help with bolts

T

ted655

Member
"I guess I need a primer on bo

"I guess I need a primer on bolt threads.
MM-fine or coarse, SAE-fine or coarse These I get. I thought my AQD40A would be metric, but on the head of an alternator bolt it has UNF stamped on it. I tried cleaning the threads with a M12-1.5 die. Close, but shaved the dia. down a bit.
I can buy a bolt, BUT I need to tap the block hole to clean the rust out. I don't want to wreak it, then I'm in big trouble.
What the heck IS a UNF & what tap/dies do I use? Thanks."
 
UNF stands for unified fine an

UNF stands for unified fine and is an imperial system. The bolt be sounds like it is 1/2 inch UNF. You sould be able to source a tap fom an engineering suppliers.
 
"It was a 7/16-20 UNF (SAE

"It was a 7/16-20 UNF (SAE-NF), but the hardness rating was metric, 8.8. (just to confuse us Yanks, I guess) I bought a new stainless steel bolt, SAE 7/16 NF. It fit perfect. Thanks for the advice."
 
Back
Top