Maximum Limit of Torque

Yes, there is.

Look it up on the web.

Engineering ToolBox

Yes. The torque at which the head snaps off.

Exactly. One of the best ways to determine the maximum torque is to flog the bolt up until it breaks, then back it off a quarter of a turn.

"until it breaks, then back it off a quarter of a turn." _{Nice touch!}

And use of a left handed torque wrench will give a more accurate reading when backing it off in the counter-clockwise direction (right handed threads only). The opposite for left handed threads. For multidirectional threaded bolts a multidirectional 3 phase torque wrench is the way to go.

Good Luck, Old Salt

Dear Mr. PWSlack,

Tightening till it breaks and backing it off for a Quarter Thread is O.K, as long as the Bolt is NOT breaking.

If, by chance, it breaks, then it is a problem and removal of the broken piece is another problem.

Then what is the solution.? Pl. Suggest.

DHAYANANDHAN.S

Which part of the broken bolt will you turn back a quarter of a turn ?

http://cr4.globalspec.com/thread/85615/Which-Bolts-are-the-Strongest

It's a little hard to tell what you are getting at exactly. You probably realize that any bolt has a torque limit.

I think you might be wondering if there some minimum number of threads required to prevent pull out or stripping, prior to the fastener itself failing. The answer is yes.

As a crude rule of thumb, for a project in which safety, cost, etc is not an issue, and where the substrate is steel, then the engaged depth should be equal to or greater than the diameter of the fastener.

However for anything to be mass-produced, or where safety is an issue, or where the cost of fastening system failure is high, then you need to do the engineering, and need to understand the substrate material properties, the fastener grade, the types of loads the fastener can see, etc.

Will the bolt head then clamp down properly on the item to be mated with said flange?

Depending on the material of the flange you may never get to the maximum torque of the bolt. If you have drilled and tapped the holes, thread depth % would also be a factor. Cast iron flanges would fail at less torque than steel. The correct tightening procedure would be to tighten until you just feel the bolt stripping out then back-off 1/4 turn. Once you feel the strip-out point you will have reached the maximum torque the flange holes will allow you to exert on the bolt.

dhayanandhan, nick name - He was joking :)

ASD23789 - Were the links and advice posted useful? If you need more help, as already stated, please provide us the dimensions, materials, application, etc. of the bolts you plan to apply torque to, and we can be of better help.

Thank you for the explanation. It was very helpful since I did not understand it was a joke. Not every body has the fine filling you have neither your humor.