From: David Beierl <dbeierl@attglobal.net>
>
> Dear John,
> Since when do UNF bolts come with grade 8.8 stamped on the
> bolt end?
>
I got companies, right now, making inch bolts with to property class 10.9 no matter what I tell them - some European companies just are not going to use inch Grade markings no matter what.

I never heard of seat belt bolts (SBB) being 8.8 grade - but yep the VW ones are marked 8.8!   I'll agree if 8.8 is on the head, it should be metric, but as I said above..... AND I've seen stranger things, such as metric heads on inch shanks, several times - stuff that would just kill us shade tree mechanics and the pros too. as I said above.

Funny though, the 45 deg tensile test for SBB's is very difficult to pass - PC8.8 would never do it - unless M12.  But as I said the non-US companies were not forced to pass the individual bolt tests the the US made cars had to.  These parts used to have an inverted triangle on the head (On SBB) - that means it is a safety part and has specific requirements.

I've been involved with automotive bolts for over 30 years now  - never seen an M11.   M7 is used on the new Jag engine in large quantities,  Some con-rod bolts are M9, but never seen an M11 (till now)!  However moot point, because of tolerance, I doubt that you can measure one and say whether it was a 7/16-20 or an M11-1.25 they are so close, although I have my suspicion that Japanese used M11-1.25

I could have supplied a thread-rolling 7/16-20 SBB - chase the threads, leave in place!!! First used on the 1964 1/2 Mustang (1/2-20 then) till today.

Anyways, too much on this already for most folks!

John