Strength of screw threads

Nov 29, 2006 1 Replies

I'm an EE so this is outside my area, but....



While looking at with a friend [his PhD is chemistry, and he writes crypto code, so no help THERE..] we go onto thread strength.



My recollection was the rule was "With good threads, the rod shall break {in pure tension} before the threads fail" but I do not know where that came from. I seem to recall that was based on a nut depth GT/EQ to one diameter as well....



But I've never seen such written down. How right/wrong am I?



David Lesher wrote in news:ekked8$640$2 @reader2.panix.com:

You are right, there is such (or should I say several similar) rule(s) of thumb. Like all such rules, they are quite useful in the circumstances where they are valid and a disaster waiting to happen in the circumstances where they are not.

Standard nuts for ordinary screws and bolts are, for example, a little thinner than the nominal diameter. A standard 1/2" nut is 7/16 thick. This is a good, conservative, well designed situation.

The general answer to where a specific threaded connection will break involves the characteristics of the nut and bolt materials, the threaded depth, and the particular thread characteristics.

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required