I am looking for a source for grade 8 bolts that are not yellow. Anyone know where I can find them?
Try Aircraft Supply. Never seen non-yellow Gr. 8s.
Without getting into a long discussion as to why you think you need Grade 8 bolts for your suspension (IMHO you donât) McMaster lists Gr 8 bolts in zinc-aluminum coated. If you were to use Gr. 5, McMaster offers in zinc plated and black oxide. I used the zinc plated Gr. 5 on my restoration.
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Tacoma Screw sells Grade 8 nuts and bolts in black. No rust resistance, but they look more period correct than the yellow. All their retail stores are in Washington, Oregon, Idaho and Montana, but they sell online as well.
You could cheat and go with stainless bolts. They wonât look original because they wonât be rusty.
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Why not have your originals plated?
Hi Harvey,
I wasnât sure what grade the original bolts were. The fastener kits offered by XKS, etc have the gold grade 8âs. Thanks for the info.
Al
Thanks Bob,
Do you know what the original finish on the bolts was? A former owner replaced everything long ago.
On an original 67 that I disassembled a couple of years ago the bolts were black, and the nylock nuts cad. They are grade 5
Carrol Smith said there was no place on a race car for a grade 8 fastener. I would assume that also fits for an E-type.
What do people have against Grade 8 fasteners? Theyâre not particularly expensive, and they are stronger than Grade 5. Seems like they canât hurt anything.
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I was wondering that as well, minimal cost increase but stronger fastenings.
I beg to differ. Iâm not particularly advocating that Grade 8 Bolts must be used; it may be that Grade 5 are adequate, Iâve not carried out a study. But there is no real argument that Grade 8 bolts shouldnât be used.
Grade 5 bolts are softer than Grade 8 as determined by a Rockwell, or other hardness test. Therefore a Grade 5 Bolt will spend more time deforming before failure. This period and area is deemed the Plastic Range. A Grade 8 Bolt spends less time in the Plastic Range, but requires over 20% more force to get there. However, a Grade 5 Bolts with this same 20+% more force applied would have elongated and failed. A Grade 8 Bolt will not have started to deform by the time a Grade 5 Bolt has reached its max elongation and fracture point.
Regards,
Bill
That statement caught my eye. I have 4 of Carroll Smithâs books, and never caught that one. In his book âNuts, Bolts, Fasteners And Plumbing Handbookâ (1990 edition) he mentions Grade 8 bolts many times with no warnings against their use. In fact, in Chapter 5, âBolt Specificsâ, he writes under the subsection âCommon Sense in Bolt Selectionâ :
âSo I also carry, in my own private stock, a pretty comprehensive selection of SPS socket-head cap screws and SAE Grade 8 bolts in various diameters and grip lengths.â
His main admonition for Grade 8 bolts, that he mentions several times, is that they can be of spotty quality and so they must be sourced from a reliable, known maker. (in those days, USA made was a criteria. Probably still holds true today, because no one is going to pay the cost to make counterfeit bolts in the United States.)
The quote from Carroll Smith, then, I assume could have been a reflection of the state of bolt quality available, or perhaps was made long before (or long after) he published his books.
Dave
âŚwhich he wanted to title, âScrew To Win,â but the publisher wouldnât allow it.
He did indeed say what bdragon said, and did not warn against Gr. 8 fasteners, per se.
You have to be careful with stainless and make sure they are strong enough. 304 and 316 grades have a lower yield stress than carbon steel
Also have the books - agree with what is said here. The illusion of quality is what he didnât âlikeâ about âgrade 8â. All critical stuff was supposed to be AN, and the SAE grade stuff for non critical stuff - if there is such a thing as ânon criticalâ in any car, not to mention race cars.
If you take stuff off any car, even old ones, the quality of fasteners is way above any hardware store stuff. The manufacturers use and have access to much more exotic stuff than ACE hardware stocks. Put a hardware store bolt under a car used in the US Midwest and see how long before it wonât unscrew due to corrosion. Our Jaguar bolts are pretty darn good - I think the highest quality steel on the whole car (some of the iron and Aluminum isnât too bad).
Another good overview of this issue, as bdragon also commented. This bolt talk is pretty good as the thread seems to offer new guys some useful info backed up with some easy to understand issues when making decisions.
I used grade 8 only because the threads were cut visibly better in the brands I found.
I wonder why he, the author, assumed grade 8 fasteners had spotty quality control and grade 5 didnât.
He was referring to the use of grade 8 as âhigh strengthâ bolts in critical application. A use where grade 5 wouldnât even be considered.
What we are referencing is a technical set of books by one author, and maybe somewhat out of date (you canât get surplus stuff much anymore). A single author, even an accomplished expert, has all the possible defects that one guyâs opinion may foster. Used as a guide this guy is pretty darn good. Iâd guess reference stuff like this needs to be combined with other information and oneâs own experience - for those who actually have experience.