Hey Alan;
Your not going to like this, but...
Somewhere in my racecar library,(I think in Carrol Smiths "prepare to win")
I remember reading that grade 8 bolts are not to be used in shock
applications (such as suspension). Too brittle, so the man said. Also," the
local hardware store" often now buys its bolts out of Taiwan , and I will
gaurantee you that if you were sucsessfully adding threads to a "grade 8"
bolt without a cobalt high speed steel die (just check what you paid . If
it wasn't $40 or more, the die isn't cobalt HSS. Mind you, thats for ONE
die, not the set!), then the bolt wasn't really a grade 8. No way. You can
barely do that with a grade 5 . Also, all high quality grade 5 and 8 bolts
have rolled , not cut, threads . Running a die down them creates horriable
stress risers and will result in a bolt that will fail under design load.
It's ok to cut treads off the end, but if you "blue" the metal or -god
forbid- get it red hot under grinding presure, you have instant stress
cracks. Since its at the end of the bolt, they MAY not cause failure.
There is a good source of affordable, high quality grade 5 and 8 bolts. The
Catapillier dealer!
Stainless steel bolts are not rated grade 5 or 8, and their washers are
not strong or hard enough to use under properly torqued grade 5 or 8 bolts.
The bolts will lose their torque over time. I don't even what to talk about
modified brake disk or caliper bolts. These are critical applications, so
get the right stuff! The bolts you buy at the hardware store may not be
safe! I know this to be the case at most of the hardware stores in my area.
You have gone to a lot of work in your bolt replacement quest. I would
strongly sugest you pick up a copy of "nuts bolts fasteners and plumbing"
by Caroll Smith . (~$18)
sorry for the rant and this in no way meant as a flame.
Don Boyd
69 TR6, Spit racer
61 TR3
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> From: Alan Myers <reagntsj@ricochet.net>
> I have been replacing all
> suspension, drive train, etc. bolts in my car with Grade 8, straight
> from the local hardware store. Nearly all have been standard NF (fine)
> thread. In a case where I needed a shoulder, I bought a longer bolt with
> the correct shoulder & used the ole Dremel to cut it down. In cases
> where I needed slightly more threads I just run a die down the bolt for
> as many extra turns as are needed. Nearly all the bolts I've run across
> are very pretty standard sizes. Lengths don't always match up, but I can
> get pretty close. I've had trouble mostly with castleated and nylock
> nuts (just due to my local store not having them, I have an alternative
> supplier, but they are not very conveniently located & short hours).
> Have done without nylocks wherever possible (Lock-tite, lock washers &
> safety wire, instead.) I've replaced lock washers with stainless steel.
> I've added flat washers where appropriate to spread out the load.
>
> Good example of what you are talking about are the bolts holding the
> brake disks to the hubs and the two mounting bolts for the calipers. In
> both cases, I found longer bolts w/shoulders & cut them down as
> described and they fit perfectly.
>
> Alan Myers (Too many bolts, not enuf LBC's)
> San Jose, Calif
> '62 TR4 #CT17602
>
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