Silver bolts
- Thread starter Paulski
- Start date
EX JUNK
Moderator
Try TOTALLY STAINLESS P.O. Box 3249, Grttysburg, Pa. 17325, (717)677-8811. I have bought grade 8 stainless from them in the past.
Jim
putz
Member
totally stainless link
Here is the link to there site.
Here is the link to there site.
Telman2
Active Member
benT
Active Member
Here we go again...
This has been covered on this site and others over and over...In the end you should install what makes you comfortable. I used Totally Stainless Grade 8+ and ARP Stainless Steel bolts on my front suspension.
I'll go get my popcorn and sit the rest of this out! :hide:
EX JUNK
Moderator
Here we go again...
This has been covered on this site and others over and over...In the end you should install what makes you comfortable. I used Totally Stainless Grade 8+ and ARP Stainless Steel bolts on my front suspension.
I'll go get my popcorn and sit the rest of this out! :hide:
Way to go, Ben! Thank you.
Jim
That's odd. Ive seen lots of specs for the mechanical properties of bolts such as proof load, yield strength, and tensile strength. Never have seen a spec for "brittleness". Perhaps you're misunderstanding the mechanical properties of the various bolt grades?
Bob
I won't use anything less than grade 8 in a suspension component. OK my turn to get out of the way.
I won't use anything less than grade 8 in a suspension component. OK my turn to get out of the way.
And I almost never use grade 8 hardware. And I never had a suspension fastener failure. And I bet I do way more suspension work that any of you. Since I am in that line of work
For the question of brittleness, It has long been thought in the automotive world, that using grade 8 bolts in places where there is vibration, like suspension fasteners, causes them to work harden and break. Is it true ? I dont know. But that is the belief. NSRA safety inspection used to say no grade 8 fasteners on suspensions. Several racing sanctioning bodies also did. So some where, some one figured that was how it is. For me, I was raised around that belief, and always used grade 5. And with no failures, EVER, I think they are sufficient.
Work hardening from vibration doesn't sound plausible. Some quick research on work hardening reveals that it occurs as a result of plastic deformation (a permanent change in shape), not elastic deformation. Highly unlikely simply from vibration. The only reference I could find regarding NSRA inspection chassis fastener requirements is that they should have lock washers, self locking nuts, Cotter pins, or safety wire.
Bob
Brucer
New Member
bout all i would use grade 5 bolts for would be building shelves with..
to work harden anything you have to have heat and quite a bit of it.. then you have to have a quench effect on top of it.. basicily crystalizing it..
i'm in tool and die, and i can tell you a grade 5 bolt wouldnt last long in a die or mold either one.. read up on tensile strength ..
to work harden anything you have to have heat and quite a bit of it.. then you have to have a quench effect on top of it.. basicily crystalizing it..
i'm in tool and die, and i can tell you a grade 5 bolt wouldnt last long in a die or mold either one.. read up on tensile strength ..
spike
New Member
It is impossible to work harden grade 5 or grade 8 bolts. The only materials that work harden are nickel based alloys such as 316 or 304 stainless steels. Grade 5 & 8 bolts are made from medium carbon steel (4140HT) which does not contain nickel. The only way to harden this material is with a torch or an oven. Work hardening occurs when nickel based materials rub for an extended period of time.
The Rc hardness of grade 5 is 25-34. The Rc hardness of grade 8 is 33-39 which makes the grade 8 stronger. In my opinion a part does not become brittle until it gets into the 50 Rc range, as I have straightened (bending on a hydraulic press) shafts that were 45-48 Rc without breaking them.
The bottom line is unless you are ramp diving your T Bucket like Evil Knievel, either bolt will work just fine.
The Rc hardness of grade 5 is 25-34. The Rc hardness of grade 8 is 33-39 which makes the grade 8 stronger. In my opinion a part does not become brittle until it gets into the 50 Rc range, as I have straightened (bending on a hydraulic press) shafts that were 45-48 Rc without breaking them.
The bottom line is unless you are ramp diving your T Bucket like Evil Knievel, either bolt will work just fine.
ChestersAlive
New Member
No one has brought up the fact that stainless steel bolts can be polished to a chrome finish with a bench grinder-mounted cloth wheel and a stainless steel compound stick.(available at Ace hardware stores) If you check out my flathead roadster pics on the forum, all those bolts you see are NOT chrome plated! The bolt heads and washers are the result of hours of polishing, and I drove that roadster for years without a problem. If I need to drill a hole in a bolt for a cotter key, I'll only use Grade 5 bolts.
My 2 cents worth............... Chester
My 2 cents worth............... Chester
Brucer
New Member
if you have a wire wheel on one side of your bench grinder you can also use that on a stainless bolt head, it gets rid of the dull look, not near polished but not the natural finish either.
Its about to get even better
Well since we are discussing car suspension, and not tool and die making, Brucer, how about we stick to info that is relavent to that ? Tensile strength has very little to do with this. Most all fasteners used in the suspension of the type of car we building, are in shear. And a lot are single shear at that. Grade 8 vs. Grade 5 is the same as chromemoly vs. Mild steel. One is more forgiving that the other. Mild steel will bend in situations where chromemoly fails. Same with the grade 5 bolts compared to the grade 8 bolts. And in a suspension system (as well as steering systems), that ability to bend, rather than break, is more desirable. Look at these pictures, specifically the bolts holding the front bars to the frame.
This is a typical set up. Whether it is a four bar, radius bars, split wishbones, they are almost always mounted in single shear. The constant pounding those fasteners take, will break a grade 8 bolt. But only bend a grade 5. That pounding is the vibration I was talking about. Maybe vibration was the wrong word to use. Flexing is probably the proper term. It is just not vibrating, there is force behind it also. That flexing will work harden the steel. No heat required. Dont believe me, go grab a piece of metal, or as I learned with as a kid, a coat hanger. Start bending it back and forth. What happens ? If you do it fast enough, it generates its own heat... And it will eventually crack.
Here are some quotes to support this found thru a google search...
"Fatigue in a fastener can cause sudden, unexpected failures. A fatigued fastener can fail even when loads are below the strength of the material due to operating under constant cyclic loads. Fatigue strength is often defined as the maximum stress a fastener can withstand for a specified number of repeated cycles before it fails."
"One of the issues with Grade 8 bolts is that there are some areas where you really don't want to use them," says Doc Hammett, Totally Stainless. "If there's a cycling load on them you could start to get into trouble."
There is no doubt grade 8 bolts are stronger than grade 5. But does the strength difference matter in this application ? A 1/2-20 grade 8 bolt has a tensile strength of 150,000 psi. The same grade 5 is 120,000 psi. Shear strength is estimated at 60% of tensile strength. The shear strength of a 1/2" bolt is approx 14,130 psi. Do you really think the rating of that grade 5 is not enough to hold up your 2000# car ? If you dont, going up to a 5/8-18 grade 5 would be better than going to a 1/2-20 grade 8. More strength and more forgiving. 17,662psi for the 1/2" grade 8 vs. 22,078 for the 5/8" grade 5. (assuming my math was correct LOL). And who is to say a 1/2" bolt in this app isnt overkill already ?
A question I always have for the guys that swear by grade 8's is why stop there ? Why not L9, why not air frame bolts ? I believe the simple answer is the others are not easy to get. A grade 8 is available at your local, home depot, lowes, ace hardware. But does any one stop to question the quality of those grade 8's ? NO. We all know the chinese are good for importing low quality products. Don't you think thier fasteners could be the same ? There steel is known to be poor quality. Now what about the quality of grade 8 vs. The aircraft hardware ? A lot of high dollar race cars use aircraft hardware. Not grade 8's. So is it safe to assume it is better ? I think so. The tensile strength of an air frame bolt is similar to that of a grade 5 (the online sources I found for AN hardware says 120,000-125,000 psi). The same theory of it is better to bend than break is used there too.
There is a lot of good advice on the internet. There is also a lot of bad advice. The problem is separating the two. The worst advice, can sometimes make the most sense to someone who doesnt have any knowledge on a subject. Do your own home work, spend a little time on google doing searches, and apply some intelligent thought to all you read.
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