Can you please go back and lube a brand new fastener out of the keg and test again??? The amount of rust on the bolt is subjective isn't it? Thus if one applies lube to a brand new fastener or one with very little rust, will it result in an over torque and over load of the bolt? This is likely. If a joint design calls for a specified lube and it is applied consistently - no problem. But the vast majority of joints/fasteners are designed for no lube. If one applies lube - it could overload the shank of the stud or bolt. Certainly there are no drawings calling out the acceptable amount of rust on a fastener!
According to Bob Shaw, if a bolt survives tensioning, it'll be fit for service in the joint because once you let off the gun, the strain on the bolt decreases by a lot.
Great video that addresses an important topic. I just wanted to mention, however, that the elongation of the bolt is essentially the strain. The tension is the force which causes this strain.
I think a more simple way to think of it is bolt stretch and clamping force. The thing is they are related, but their relationship can change. When a bolt is yielding, it changes their relationship. The bolt can keep stretching while the clamping force actually decreases. You can feel this if you have ever tried torquing damaged/yielded wheel studs. They won't tighten to spec, they will keep turning until eventually the stud breaks.
Yes, when using a lubricant this effects torque specs! When I was very green, an old school mechanic told me to be careful of this! Happened to be my big Brother Eddie. Keep this in mind when torquing your bolts. What you do about it is up to you, your in control. Under God.
Back in the early days, I would regularly hear that certain competitors bolts were better quality than mine. Then a smart man cane along and taught me this. Never lost a deal after on perceived quality
i think you'd just be helping it to reach the amount of stretch/preload a fastener of that material and size was rated for. i'd be inclined to say that even if you compared two new bolts, one lubed and one not - you'd reach a higher preload on the lubed one for the same torque. of course if they are torque to yield bolts then its a different story
My 2000 F-250 manual advises me thusly: On all two-piece flat wheel nuts, apply one drop of motor oil between the flat washer and the nut. Do not apply motor oil to the wheel nut threads or the wheel stud threads and... On vehicles equipped with single rear wheels, retighten the lug nuts to the specified torque at 800 km (500 miles) after any wheel disturbance (tire rotation, changing a flat tire, wheel removal, etc.).
I bought tires at TireRack at the South Bend, Indiana location. After they installed them I had to sign a form stating I'd retorque them after 50 miles. Same thing.
I'm not expecting an answer on a 13 year old video, but I'll try anyways. Will a lubed bolt assembly not have a greater chance of sliding out after a while and lose tension since the threads are lubed?
This is one of those. "I didn't know the building was loose" kinda of conversations you say to lawyers in court. This is not common knowledge and could easily be overlooked to end in catastrophe.
The lower the coefficient of thread friction the bigger the chance of that bolt coming loose. The thread lubrication of carbon steel coated fasteners is normally not necessary. After a prolonged service interval however, a PTFE lubricant can be used to reduce the friction coefficient.
My car is 32 years old and I'm more than twice that, so I meet long time lubrication problems, often at the lug bolts. I'm not in socal any more, but soggy eastern NY where they use salt on the roads in the winter. My lug bolts effectively seize up (only partially, thank God) due to the threads being freed of all lubrication by repeated washings of water, especially at the bolt "cone" juncture with the countersunk holes in the alloy rim. The steel and the alloy do their best at trying to become one with each other at their joining surfaces over the time of one year or more. The "mechanics" with their air impact weapons can't or won't take the time to assure that the bolts are brushed clean of foreign material, which adds to the problem. To get to the point, when I detect that there is a problem with the lug bolts at a wheel, I clean off the threads (at least on the bolt) and apply a thin amount of Permatex anti-seize compound (the dreaded "gray stuff" feared by mechanics everywhere) to both the threads and the "cone." The metal particles do a better job of remaining over time than would just plain oil or grease. Then, I tighten by using a lug wrench and I can feel (judging by the size of the bolt thread [in my case 12 mm]) when I am tightening by elastically stretching the bolt, and not plastically deforming it towards breakage. I have never had lug bolts loosen, and the anti-seize compound is much better than risking a broken bolt when removing a wheel.
When torqueing we can only rely on the manufactures specs for minimum and maximum lb.-ft. and keep the indicated value between them. However, this value does not indicate tension but rather the combined amount of both tension and overcoming friction. So I wonder when using a lubricant on the nuts which reduces friction, is the indicated lb.-ft. on the torque wrench still within the min/max or exceeding the max. Perhaps it's moot but I've seen a lot of lug nuts with studs still in them laying in the street.
When talking about wheel studs/nuts, I never hear about replacing studs on any regular basis. Don't Wheel studs stretch over time? Would that cause breakage with the same torque applied?? I'm still learning
buenas tardes, tengo una duda; si tengo un tornillo de 1 1/4 A490 para un tension de 116000 lb aproximadamente y necesita aproximadamente como minimo unas 3900 lb para que quede torqueado el perno; pero en la pistla solo esta hasta 2200 libras; como hago para que me llegue a las 2900 lb necesarias ?
Por favor, en ingles: "Good afternoon, I have a question; If I have a 1 1/4 A490 screw for a tension of approximately 116000 lb and it needs approximately at least 3900 lb for the bolt to be torqued; but the pistol is only up to 2200 pounds; How do I get the 2900 lb needed?"
@@appliedbolting He asked: "Good afternoon, I have a question; If I have a 1 1/4 A490 screw for a tension of approximately 116000 lb and it needs approximately at least 3900 lb for the bolt to be torqued; but the pistol is only up to 2200 pounds; How do I get the 2900 lb needed?"
If you lubricate a bolt then you reduce the required torque for a set pre-tension, however, you also greatly increase the chances to break the bolt or the clamped parts. VDI2230 standard advises correct torque calculation and provides achievable pre-tension ranges for bolted joints. Never lubricate a bolt without understanding tension/compression capacities of the joint.
Also depends on your lubricant, motor oil is alot different than greese but both lubricants. I use oil sometimes, greese be very careful, may torque to a minimum load then use angular torque like with a stretch head bolt. Good thinking.
So your saying the bolt has 14,000 lbs of over-tension. WOW! Too much tension and Too much torque are the #1 cause of joint failures. How is 53,000 lbs or tension acceptable when only 39,000 lbs are required?
you could have a reduction of bolt cross section with strain due to poisson contraction but if it's a friction connection it's fine unless it's a really long bolt (say >10xdia.) which could then become loose after relaxation
Too much tension and too much torque are the #1 cause of joint failures? Where can one find the information you used to base this statement on? I disagree with what you. I believe it is to little tension which is the #1 cause of critical bolted joint assemblies.
@@jimbob7218 I think both too little and too much torque can result in joint failures. For too little, shearing may occur. In any case, check this YT video and see if that helps. It was insightful for me. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-g_CdH3RJc04.html
@@jimbob7218 it's A.S.M.E. code and all bolting courses teach this. It's even in John Bickfords 1000 page bolting books. Overtightening and stretching the threaded bolt past its elongation will cause broken bolts.
