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internal thread testing

M. Roberts

May 11, 2021
Hello, I hope everyone is well. As part of the neverending saga to produce good threads in our 55% SiC/aluminum composite, we have purchased a Skidmore Wilhelm Bolt Tension devise. To my understanding, this is how it works; using two large washers, and the test bolt and/or nut, you tighten it up (real tough so far, right?) compressing a hydraulic cylinder. Not too complex. I saw the unit for the first time yesterday...the issue is that the gages are way (imo) too coarse; they are in lbf x 1000 increments..again, way too much for M5 threads that are questionable in nature. Does anyone have any experience with these units? are there gages available of finer graduation?

Thanks in advance,


Diamond; Mod Squad
Mar 27, 2005
Northwest Indiana, USA
I'm sure you could devise something a bit finer pretty easily. I could see making something out of my Enerpac load cell for instance. It's graded in 100 LbF increments up to 10,000 pounds. The ends have female threaded holes so could easily accept some form of threaded fixture. Tighten the bolt until the thread fails, then read the red arrow. There are probably finer increments available, or you could just calibrate your own pressure gauge.

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