If you take a grade 8 bolt lets say 5" in length. 3/4 of the bolt is unthread and the other is threaded. If one was to cut off head and run the unthreaded potion through a die and thread it making a double ended stud would it effect the strength of the bolt?? I need to make a double ended wheel stud that is not available. I had done the same to a starter bolt and when it kicked back it cracked in the newly threaded portion. I am no metalurgist so I want to be sure this is ok as they are wheel studs?? What could be effected??? Thanks
A grade 5 is case hardened unlike a grade 8 which is thru hardened - so you have a better chance with a 8, but the grade 8 is also likely to be roll threaded which does also alter the grain structure resulting in increased thread strength. So I would think you'd end up compromising the thread strength some - how much - I dunno. If it were me - I'd look long and hard to find a wheel stud "off the shelf" - if for no other reasons than the shear liability. (pun intended)
If you try to cut threads in a grade 8 bolt, all you really do is create stress risers, and yes they will crack! Why not buy a grade 5 stud at the bolt store. Grade 8 is to brittle for wheel studs. just my 2c Jeffrey
I'm thinking wheel studs are soft. They can bend, you can strech them before they break, and you can strip the threads. I think for the toughest, most durable stud you'd want to make it out of an allen head bolt. American, not Chineese.
Just a little caution on the Allen Head bolts, the 'Unbrako' brand bolts are Grade 12 min, so doing anything to them is out of the question. My suggestion would be a mild steel bolt, but of a good grade say 1030L, you may have to source some round bar from an engineering shop or supplier. You definatley don't want high grade bolts (or studs) holding you're wheels on. As has been noted earlier, in the case of failure the studs must deform (and still retain the wheel) instead of shearing and losing the wheel. Also the studs are the sacrificial part in the assembly, they should fail before doing damage to the hub or rotor.
If you dont need them 5" long, studs for drag cars are about 3" long with threads all the way and you run them in from the back. Wilwood and several others use them that way.You wouldnt have to cut them off.
So much wrong with these statements. First off, GR8 bolts are not brittle, they are tougher. In every instance you can put stress into a bolt, GR8 bolts will exceed stress and load standards of lower number grade bolts. I have no idea where this notion of "brittleness" is coming from but it needs to be killed dead. Cutting threads in GR8 bolts with standard taps and dies might be a bit too difficult to do because of the toughness of the bolt. As far as creating "stress risers", I can't see any more potential than rolled threads. Would you care to share some data showing any support for your claims? Here are a few "wives tale" free sources of information about bolts. http://www.boltscience.com/pages/failure4.htm http://www.portlandbolt.com/faqs/grade-8-and-astm-a325-bolts-compared http://www.rockcrawler.com/techreports/fasteners/index.asp Just note that proper torque is very important to the joint strength and the longevity of the hardware. Regardless of materials and ratings.
At least I know it wasn't a stupid question. It is a rare Renault race car that has 12mm stud. Cant install from back has to screw in from front. I am going to look a bit harder as now I am a bit more concerned then I was before. Interesting reading. I just don't want to do something on a safety piece without research hate to have someone get hurt on my backyard repairs. Thanks
http://www.grainger.com/Grainger/double-end-threaded-studs/bolts/fasteners/ecatalog/N-8jx/No-16 Don't know the dimensions of what you need, but ^^^^theres^^^ 340 flavors. I'm sure there's more out there. Also all thread is available in different grades, not at home depot but its out there.
Do not screw around with wheel studs unless this is a museum piece that won't see any street use and especially track time. The loads wheel studs see on the race track are tremendous and inventing wheel studs for any race car isn't a good idea. There is a difference between rolled and cut threads in fatigue resistance. Check out ARP's web site along with the good ones ElPolako posted and this one as well http://www.eng-tips.com/viewthread.cfm?qid=88946 You can call ARP's tech line. They'll explain what options you have and they do make fasteners for lots of things besides cars so chances are they'll have what you need or can point you in the right direction. -Bigchief.
Won't matter what kind of bolt you use it will effect the thrength of it if you cut new threads. "Cut " being the operative work here. Bolts that ou purchase have the threads rolled on them not cut. When you cut threads you make a shear point that a rolled thread doesn't have. When I need a wheel stud that is threaded into the flange and can't find one I snag an allen bolt in grade 8 that is long enough and threaded alll the way. I'm sure a hex bolt will also work but I have found it easier to find allen bolts that way around here. Then I cut the head off clean the threads to make myself a good starter thread and use it. Works like a champ.
These are a rare find as I have been on the net all day. Grainger.Maccarr, etc, etc, 12mm 1.25 57mm long 3/4 center unthreaded. I can't even find a bolt that would have long enough thread to cut head off for under $8 and even then they were unsure. There are 2 small co that might be able to make for me. Never did I think this would be a hard find. They are readily available in the UK but only one co out of like 50 would even entertain shipping. They are getting back with amounts. I agree with modifying stuff. I am quite capable of making stuff but I have learned that you can't know everything about everything and some risks are not worth it. Thanks and great info on a simple item.
Any good tool maker can make you a bolt. All that is required is the correct steel and the threads can be chased on with the machine. Then it can be hardened in an oven to the correct Rockwell. He might charge more than 8 dollars though,,LOL. Tommy
I dont know if this has been mentioned, but as far as I know, mass produced bolts are not cut. They are rolled, which leaves the grain of the steel intact. You cut through the grain when you cut the threads, so the cut bolt would be weaker.
AND !! The un-threaded shank of a rolled thread bolt is undersize. Meaning you can not get a full thread buy cutting with a die or on the lathe. By the way grade 5-8 etc bolts are not CASE HARDENED !! ,heat treated yes ,world of difference.
Rolled threads are much stronger due to the work hardening of the material during the rolling. The topic of nuts & bolts is very complicated & confused by many myths. The late Carroll Smith's book on the subject is by far the best at explaining how to safely put a car together. He wanted to call it "Screw to Win" after his other books "Prepare to Win", etc were so well received but Steve Smith Motorbooks nixed that idea. High strength all thread rod is heat treated alloy steel with rolled threads. I buy it from McMaster & Carr in 4 foot lengths. Wheel studs are especially worrisome. I once bought several thousand for a work project only to find they were rejected by Ford due to a coating error. Tightening them to full strength resulted in 100% failures. Every stud in every hub drive pulled apart. Buyer beware unless you deal with a reliable supplier like McM & C or Fastenal. Chuck Schultz Winfield, IL
Good advice right there. PM me with details. I am friends with the ARP owners and the owners of Federal Manufacturing (make all the fasteners for Boeing) and I'm sure I can hook you up with proper stuff. Keep in mind a wheel coming off at almost any speed WILL KILL SOMEONE who is hit by it.
THANK YOU! This happens everytime someone talks about bolts, all the wives tales about stretching and other BS come up. Let's keep working to rub them out!!!
Per Carrol Smith's book " Engineering to win" cutting additional threads whether with a die or a lathe will leave a stress riser at the root of the thread and weaken the bolt. I've seen wheel bolts that are threads thru from the back side of the axle or hub and used with a lug nut, but don't know if this fits your application.
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