Needed some bolts for the steering arms on a 48 Plymouth so naturally bought grade 8. Inside of rotor was brushing the head of the bolts so chucked up in lathe and being grade 8 figured I'd have to grind them. Carbide tool was in the holder so decided to give it a try---cut like butter. Traded carbide for HSS tool and still cut off big bites. Chucked one of the nuts up and same thing. Then used hack saw with a HF blade and sawed a groove in one. The nuts/bolts came from Fastenal but I'd be every supplier has the same fake Chinese bolts. For control I dug up some ring gear bolts for a 37 Buick and flywheel bolts for a 46 Ford. Hack saw blade would just leave shiny mark but not cut at all. If someone like ARP actually has real American hardware that's what I'll buy and damn sure not pay big bucks for grade 8 when I'm not even getting grade 5.
I wouldn't want through hardened bolts on my suspension, they would be too brittle and snap. Grade 8 means they have a tensile strength of around 150,000 pounds and a shear strength of around 60% of their tensile strength. They are also ductile which is what you want. This is given they are actually torqued as required with a torque wrench, not "mechanic's feel".
Same reason you don't QUENCE any front axel or spindles in water or any other forged part after heating and bending. It makes it brittle and you don't want brittle. Grade 5 bolts are more brittle than grade 8.
Be sure to get back to Fastenal about the problem and raise hell. That is the only way we can stop this kind of problem. Maybe they are not even aware of it. I remember when a bunch of crappy fasteners got into the space shuttle, that was a very expensive rework. Charlie Stephens
Are you substituting a grade 8 bolt for a "Hardened" bolt? Are they not two completely different things? With two completely different jobs.
Hard is brittle and grade 5 are not they usually are nickel plated which is soft. Grade 8 bolts are stronger bolts. Harden bolts have different head sizes example 1/2 grade 5 or 8 bolt has a 3/4 inch head and a harden bolt has a 7/8 head Sent from my SM-G925W8 using Tapatalk
Quench, and I'm not sure Grade 5 is more brittle than grade 8. There’s an argument that grade 8’s are more brittle than grade 5’s and that argument claims you shouldn’t use them. Well, first you need to understand what the term “brittle” really means. Brittleness in bolts is defined as failure at stresses apparently below the strength of the bolt material with little or no evidence of plastic deformation. Typically, fasteners are not brittle below 180 ksi ultimate tensile strength. Grade 5’s have an ultimate tensile strength of 120 ksi and a grade 8 fastener has an ultimate tensile strength of 150 ksi. This is why brittle is a relative term. Nearly all fasteners are considered ductile except some made from PH 15-6 Mo, 17-4 PH and 17-7 PH. Some of this info is copied from: http://tinelok.com/grade-5-vs-grade-8-fasteners/
OK, But was not the comparison stated by the OP, between a Grade 8 and a Flywheel bolt and a bolt for a ring gear. Are those two "NOT" hardened bolts?
The sad part may be....that's all they can get now! But to charge for grade 8 and not being grade 8 IS something they can do about it!
Over seas manufacturing can make any range of quality, they make the quality the US company wants to pay for. Calling their parts junk is talking trash about our US companies, plain and simple.
purchased four boxes of hose clamps a few weeks back, they all stripped when hand tightening with a nut driver as soon as all the slack was gone
I've been taking a cleaned assortment of gennie ford bolts to the local swap meets for over a year and nobody has even asked about them. The old Ford bolts have no markings on the heads and I was once told they're a grade 8 bolt. They're all chassis bolts and engine bolts. I'd have no problem using them in a high load situation. Now that China has saturated the bolt market, I believe I'll just keep them.
Almost all fasteners are now made over in China or the like .I'm an ironworker by trade and see it everyday the quality go more and more south . We just can not compete with China for labor costs and the fact both the Canadian and American government didn't catch on to China buying such huge amounts of ore till it was to late. They need to throw tariffs and huge penalties for companies cheaping out and buying the shit as their own Sent from my SM-G925W8 using Tapatalk
This might be true about US companies outsourcing for more profit but most chain hardware stores carry brands that are made and owned by foreign countries. The only US connection is the mark up at the store. Unfortunately this is where you have to go when you need a part to get your car home or make an emergency repair at your residence.
They bought all our tooling and equipment at scrap price too. Get the scrap price high enough and everything went. God help us if china gets pissed because we won't have ANY bolts to bitch about. Nor could we make them.
I really don't think that is valid means to determine if a fastener is grade 8 or high quality. I've cut down high quality made in the US ARP fasteners, and wheel studs and they cut quite easy (hacksaw or band saw) and hit them on the belt sander. There is a lot more to it. Here's some good reading. Note in the metallurgy tab: With steels, as the strength goes up, the toughness decreases. At too high a strength, the metal tends to be brittle. And threads accentuate the brittleness. A tool steel which can be heat-treated to 350,000 psi, would be a disaster as a bolt because of the threads. http://www.arp-bolts.com/p/technical.php#p7TPMc1_4 I bet the Fastenal brand are actually pretty good.
Maybe some of the U.S. companies need to request a higher quality in the products they have made over seas?
Most everything is built or speced out at bare minimum requirements. That is because only a few people are willing to go beyond bare minimum. Folks drive 5 miles out of the way to save $1.00 on tank of gas, they will drive 15 miles to save $2.00. They do the bare minimum on their jobs, ride around on overdue repairs, they also don't want to get raped on bolts and hardware. Example - seems kinda high, $2.00 for 10 pieces. 20 mins earlier Napa sold my buddies wife 6 connectors exactly like these for $12.00 @ $2.00 each. ARP stepped up to redesign a FORD bolt/stud because they break. Costs you $159.00. Ford sells them for $27.00 each BUTTTT,,, they are special order and come in 4 packs and you need to buy the whole pac. Costs you $108 to get the one you need/ That is exactly like the one that broke off flush in the differential. Ever have one of these let loose? Car dives like a forklift with busted pitman arm.
View attachment 3530206 Doesn't everybody have access to a Danly 250 ton press to make their own bolts? We still make bolts here, this is the start of the bolts for the fuel tanks on the Space X rocket.. Inconel. Good stuff.
There's a lot to learn about automotive fasteners and a few really informative books out there about the subject - what I have done for my race cars and hot rods is used AN hardware (aircraft bolts) that I buy from Aircraft Spruce, paying attention to grip lengths (the unthreaded part of the bolt) and making sure that critical suspension brackets and such use the fasteners in double shear, whenever possible. All the fasteners used in the suspensions on our hot rods don't come to a lot of money compared to the cost of suspension failure at any speed.
I used to buy grade 8 bolts all the time, until I learned there proper use. They break before they stretch, thus more Brittle. Grade 7 will stretch before breaking thus appear more stronger. Only use grade 8 in non moving parts like motors and such. Grade 9 would be like aircraft. But not exactly.
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