Threaded Rod Tensile Testing

[jzhaan55]

I want to do a standard tensile test on a A36 threaded rod (1"-8 threads). I was planning on threading large steel plates to the top and bottom of the rod so that the tensile tester can clamp onto these plates for easier mounting. Is there a way to calculate the minimum thread engagement length needed to ensure that the rod is not stripped out of the threads before the rod breaks? A36 steel has a tensile strength between 58 and 80 ksi.

 

[SnTMan]

1 1/2 D usually works

Regards,

Mike

 

[jzhaan55]

Awesome thanks. If the max tensile strength of A36 is 80ksi, how do I calculate the maximum load that a 7/8"-9 rod could theoretically take?

 

[SnTMan]

By referring to Machinery's Handbook, which covers the subject pretty extensively. Failing that there is always Sigma = P/A.

Regards,

Mike

 

[racookpe1978]

Remember, the "area"above in his formula is for the root area (not the max diameter area) of your 3/4 rod.

Further, you buying an "average" (or maybe a cheap Chinese imitation!) of an "average" A36 piece of steel. What is its actual strength? Are you sure you really know the baseline strength of what you "think" "should be" 36,000 psi?

At this level of calculation - you also need to actually measure the diameter and actual thread depth. Don't "assume" your book values are correct.

 

[Metalguy]

Should break before you reach ~37,000 lb.

"You see, wire telegraph is like a very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? Radio operates the same way: You send signals here, they receive them there. The only difference is there is no cat." A. Einstein