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Hmmmm are grade 8's supposed to snap at 90 ftlbs?
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Logistics Pro
Joined: Jan 2001
Posts: 3,789
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From: Connecticut
Hmmmm are grade 8's supposed to snap at 90 ftlbs?
Started torquing down the crossmembers on the F-5 with grade 8's.
Thought I'd crankthem down to 100 ftlbs.
They snap at 90, Is this Normal?
Thanks
Reamer
Thought I'd crankthem down to 100 ftlbs.
They snap at 90, Is this Normal?
Thanks
Reamer
old and in the way
Joined: Jul 1997
Posts: 5,921
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From: Lovely Hueytown Alabama
George !!!
you beat me to it.... I googled for a while before I found this.... lots of torque specs for specific applications... like to never found a general bolt spec sheet...
so see Reamer ?? it depends on bolt diameter not just grade... I've got the titanium specs if you need them too
George ??? have you EVER seen a Grade 7 ???
john
you beat me to it.... I googled for a while before I found this.... lots of torque specs for specific applications... like to never found a general bolt spec sheet...
so see Reamer ?? it depends on bolt diameter not just grade... I've got the titanium specs if you need them too
George ??? have you EVER seen a Grade 7 ???
john
Postmaster
Joined: Mar 2000
Posts: 3,730
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From: Waynesville, OH
Nope, don't think I've ever seen a grade 7. Not sure I've seen a grade 6 either. Here's another chart with torque specs for other materials. Might stick them both on Earl's World in the reference section if anybody thinks they might use them.
Posting Guru
Joined: Apr 2002
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Ever seen a grade 7?
Penn Dick saw it.
For three consecutive years, from what I heard.......
Then there was high school...the best 8 years of his life...
BWAH,HAH,HAH.......
Penn Dick saw it.
For three consecutive years, from what I heard.......
Then there was high school...the best 8 years of his life...
BWAH,HAH,HAH.......
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Fleet Owner
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From: NM
The effect of lubrication on the torque required can't be overstated, one reason you don't lube wheel studs!
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It may not be the problem here but it seems out Asian friends aren't necessarily doing things as they should. There is a picture in this link of some defective or suspect grade 8 bolts. Hope it posts.
http://www.hotrodders.com/t64273.html
Click on the doc file in the first post.
http://www.hotrodders.com/t64273.html
Click on the doc file in the first post.
Postmaster
Joined: Mar 2000
Posts: 3,730
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From: Waynesville, OH
Good info John. A bad bolt could really ruin your day - especially if you find out it's bad while driving! 
There are a couple brands I use that have pretty good QC. All Holo Krome stuff is made in the USA. We've also had good results with Unbrako products, although I don't know if they are all made in the USA.
As far as the original problem goes (Mr. reamer with the BIG wrench), the only screws I could find, even in the aerospace specialty catalogs, that can withstand an onslaught from reamer's 90 ft-lb wrench in a 3/8" diameter are some Maraging steel hex bolts with strengths of about 290,000 psi (versus 150,000 psi for grade 8). At $35 a pop though, you don't want to be breaking those babies off left and right ... er ... right and left. Ummm, let's see, righty-tighty, lefty-loosey ... oh, whatever.
There are a couple brands I use that have pretty good QC. All Holo Krome stuff is made in the USA. We've also had good results with Unbrako products, although I don't know if they are all made in the USA.
As far as the original problem goes (Mr. reamer with the BIG wrench), the only screws I could find, even in the aerospace specialty catalogs, that can withstand an onslaught from reamer's 90 ft-lb wrench in a 3/8" diameter are some Maraging steel hex bolts with strengths of about 290,000 psi (versus 150,000 psi for grade 8). At $35 a pop though, you don't want to be breaking those babies off left and right ... er ... right and left. Ummm, let's see, righty-tighty, lefty-loosey ... oh, whatever.
Fleet Mechanic
Joined: Jun 2004
Posts: 1,777
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From: Minnesota
If you are worried about them coming loose use LocTite or some other thread compound. Yu can get varying types. For instance if you already have them installed you can get Loctite 290 which is a medium strength wicking grade. If youare going to use loctite make sure the bolts are clean nothing sticks to oil very well.
Originally Posted by reamer
Thanks Guys
These are 3/8" Grade 8"s,
Just seems funny, ya want ta crank the #$*&@ out of em' to keep the frame tight yet the torque specs tell ya to be on teh "loose" side
These are 3/8" Grade 8"s,
Just seems funny, ya want ta crank the #$*&@ out of em' to keep the frame tight yet the torque specs tell ya to be on teh "loose" side
Fleet Owner
Joined: Jul 2004
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From: NM
LocTite is a great idea. Unless you plan to drop the crossmember for trans work in the future, and if the bolts are out, LocTite 271 is virtually permanent, "heat may be necessary for removal". It's used on flywheel bolts sometimes.
Hotshot
Joined: Oct 2004
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From: Durham NC
Originally Posted by ALBUQ F-1
The effect of lubrication on the torque required can't be overstated, one reason you don't lube wheel studs!
I will agree however that the tapered surfaces of the lugnut and wheel should never be lubed since the wheels are actually held on by an interference fit between the two tapers NOT by clamping force generated by torque stretching the stud. This is a discussion that comes up regularly on the racing forums.
For strength you can't beat ARP bolts, the only brand in a NASCAR engine.
Last edited by AXracer; Jul 7, 2005 at 10:30 AM.
Fleet Owner
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From: NM
AX, On a race car where you are constantly removing/installing wheels, I'm sure it makes sense to lube. You are actually stretching the bolts much more than designed for (which may be appropriate for racing) if they are lubed.
I'd be interested to see a link to a thread on the interference issue; that must be for a particular type of wheel configuration. I can't see why lube on the seat would matter if it is an interference fit? Typical HD trucks (semis) use clamping force (no tapered seat) plus the centering provided by the hub, one reason they have a bejillion nuts.
I'd be interested to see a link to a thread on the interference issue; that must be for a particular type of wheel configuration. I can't see why lube on the seat would matter if it is an interference fit? Typical HD trucks (semis) use clamping force (no tapered seat) plus the centering provided by the hub, one reason they have a bejillion nuts.
Senior User
Joined: Jul 2004
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From: Culpeper, VA
I don't see any reason why you can't lube anything you want on your wheel studs, including the tapered mating surface, although I don't know why you'd want to. I'd never heard of the interference issue either, I'd like to see an article on that. The lug nuts ARE held on by friction at the mating surface, but once you tighten them past a certain torque (pretty low), lube makes no difference.