The Jalopy Journal
Discussion in 'Traditional Hot Rods' started by coilover, May 10, 2017.
You don't find grade 8 bolts on aircraft, most everything is grade 5!
Lots of good info there, and lots of fallacies explained. I threw away all my lock washers years ago after reading about them, and watching the video where the bolt with the lock washer loosened sooner and faster than the one without. Ever see a regular lock washer on an airplane either?
They also explain where to use a grade 5, and where to use a grade 8. One has better shear strength, and the other has better tensile strength.
I have a little story regarding grade 8 bolts. I grabbed a couple 3/8ths grade 8 bolts from where I once worked. They bolted sign posts to concreted-in stubs and they were brittle enough to snap off if a car hit the sign. Welp, I figured using a couple to bolt up the oil pump in my new 389 Pontiac motor wouldn't put a shock spike to the bolt like a car collision would. And they're grade 8 so they're really strong, right?
Things went really good 'till the third day. The morning was chilly and when I lit off that 389. it began to click...oil pressure was zero! Shut it off and pulled the pan to find the oil pump in the bottom of the pan. Those brittle grade 8s snapped like icicles. Installed the original pump bolts and lived happily ever after. The end.
Fellas, I've had to clean up this thread, keep the politics and racial content out please. This is a good conversation to have, don't spoil it.
Here down under same problem, bought some shit 8's, they were plated silver colour. Chucked 'em, went to Caterpillar & bought some there. Black ones.
Welded a new drawbar onto my car trailer and asked a local mechanical engineer about bolts for attaching the coupling . I thought that high tensile would be the go but he said no, grade 5 from the local hardware would be enough. His argument was that in that situation you are better off having the bolts stretch rather than snapping. Just keep an eye on the bolts and nip up the nuts if loose. This trailer had no springs, just solid mount axles and the bloke I sold it to is a scrapper who loads this trailer up to max.
I also cut grade 8 bolts in the lathe, cut them with hacksaws and drill holes in them. and mine come from a different source.
How is that thing on walnuts?
I find that Ace Hardware has some very good grade-8 hardware. One bolt I mad to modify, head was too high and the best way to tackle it was using a grinder. They have a grade of stainless steel bolts that has to be an A286 alloy, they are real nice.
Not much in common between aircraft AN grading/applications and SAE grading.
But I got to tell ya - sometimes those castellated nuts or a row of safety-wired bolts look really cool.
The shear point of a grade 8 bolt is much higher than a the "stretch" point of a grade 5, in other words grade 5 will stretch, snap and be gone way before a grade 8 will even begin to be stressed. Grade 8 are not brittle.
What he told you was to put in a weak bolt because it's weaker. They may have been strong enough for your application but they are not in any way better than a grade 8.
One of the books I mentioned is Carroll Smith's "Nuts, Bolts, Fasteners, and Plumbing Handbook", still available at Amazon, and something I think every serious rodder should have in their reference library. While I haven't seen it yet, I expect the Mike Mavrigian is good, too.
I have never seen a "soft/bad" grade 8 bolt, yet. Where I work, I purchase grade 8 fasteners in bulk from MSC, you have the option to purchase American made or overseas made. Same goes for my projects, nothing but quality grade 8 unless I have good useable "vintage" Henry Ford fasteners.
Did you swipe it one piece at a time? and didn't cost you a dime?
Roger that, great book.
that sucks hard to fine anything good in the USA to bad we get all JUNK now NEEDS to STOP
On the '46 Ford bolts...I believe the modern grade 5 and 8 date to the '50's. Ford and others made or ordered bolts for the application...on high load stuff like engine fasteners and safety stuff like suspension they got the strength they needed. I have unbolted early Ford suspension fasteners that were rusted to the point that I had to put a pipe over my breaker bar, and the fasteners were almost 50% missing from rust, and had them unscrew properly rather than failing. Restorers have failure tested the COMMON Ford bolts (meaning not the special ones for suspension, etc.) and say that even those holding on the fenders test out over a range between 5 and 8 in modern usage. I've had similar junkyard experiences with Nova bolts...not failing even though horribly damaged by years of salt. I note that those bolts were also not marked with grade lines...presumably GM, like Ford, ordered the bolts by needed safety factor and they may be more like aircraft spec bolts designed for very high safety margins.
I have Ford texts on some fastener issues, on metallurgy, and at least elementary engineering...very high standards, with systems in place to describe strength and thread penetration, but NOT on the 5 and 8 system. Ford even did 100% Brinnell testing on some production steering parts to verify spec...We need a more sophisticated vocabulary here than "Hardened" and "tough"...all that is really much more complex. My inadequate understanding is that all or most treatments start with HARD, as in heat and quench, then move toward TOUGH by heating to a lower sub-critical temp with elaborate cooling schedue to restore real strength. And hardened bolt...? No one has a use for a bolt that is just HARD. Bang! I think most bolts so described are surface hardened, a completely different sort of treatment, to produce contact surfaces that will not be eaten away by heavy load working on bolts that are not otherwise super hard. Just a misnomer.
I wish I had the knowledge and reading time to pull together all the early Ford metal working stuff...
I built myself an airplane a few years back, and found that you tend to be very careful with hardware selections when you're going to be putting along at 10,000 feet in something you built yourself..................
On the letters above...Smith's biggest point on 5 and 8 bolts is that while there are specs, there is NO policing at all. Th Chinese can put as many lines as they want up there on ANYTHING. He also mentions that SAE grade bolts are not allowed at all for aircraft applications.
If I'm not mistaken Smith mentions Supertanium (real name) bolts.
Be glad you're not looking for them!
I'm no expert and don't know diddly about bolts......
but I might actually have a useful tip about hose clamps. Namely, throw away all the clamps with perforated holes in the bands. Buy only "European" style hose clamps.... the ones that are groved to mesh with the worm gear but not punched through. 10 or 12 years ago, I was messing with turbocharged cars and lots of hoses had to be super tight to handle high boost pressures. The extra torque needed to handle boost tended to cause the perforated bands to fail where the "Euros" didn't. Plus, the un-perforated, Euro bands won't extrude/cut the rubber (in my case, silicone) through the holes which will weaken the hose integrity. A drawback is, you may have to shop them on-line unless you're lucky enough to have a local store that carries them. To me it's worth the extra time and effort to get the great results.
Even the dam plastic zip ties and duct tape is junk now....
It's all undersized too.
Try to find 2" tape or 3/4" tape - I went nuts a while back.
You can still get good zip ties, but not 1000 of them for $20.00
Or you can get 50,000 in various sizes 4"-36" for free. Guess it paid to know a manager at GB Gardner Bender. I think I can live to 200 and still have some.
I fly an airplane. Imagine how nervous I get with these fake, junk fasteners. It is a real problem.
That's a perk, not reality for the rest of us.
This still makes me laugh.
“As I hurtled through space, one thought kept crossing my mind - every part of this rocket was supplied by the lowest bidder.”
― John Glenn
Good thing they didn't have to go 250,000,000 miles and back.
Definitely not traditional!
Legend is that one of Henry Fords engineers told him his wheel studs were stronger than they needed to be and he could save money by using smaller ones. Ford had him take one of the smaller size bolts and tighten it as tight as he could and it broke. The engineer told him that they don't need to be torqued that tight. Ford said they don't need to be but they will be.
I don't think China buys ore, they buy scrap metal and lots of it.
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