Tough Nut

Tough Nut
	Post Reply		Forum

Posted by: Agis ^®

07/05/2007, 02:45:25

Author Profile
eMail author
Edit

I am looking to change hardware supplier and had several nuts by a new supplier tested. Some of the results trouble me and I wonder if anyone has some advice to help me out.

The fastener is an M12 steel nut, Grade 8. It fits on a grade 10.9 stud (the nut is long enough to take the extra torque). Torque specified is 110Nm.

The first test is a "clamp-load vs. number of times tightened". The test torque was 110Nm and each nut was tightened 20 times.
The test results between the two nuts are very different (see graph 1).
Question: What can I tell from this result? Is the new nut better than the old?

The second test I requested for was to measure the torque needed to achieve 70kN tension on the stud. Our specification requires the result to be between 105 and 150Nm.
The test ACTUALLY carried out was different. They measured the tension on the stud at 110Nm (see graph 2).
Question: does this test tell me anything about how these nuts would behave under the specified test or do I need to re-test?

Post Reply
Tell a Friend (must be logged in)
Alert Admin About Post