RE: Torque Wrench Dillema - 3

A slight digression ….

Back in the 80s I was a young engineer on a petrochemical plant directing fitters who were flange tightening on large heat exchangers and reactors using ultrasonic bolt tensioning equipment. I was measuring bolt stretch on large diameter bolts up to 2.1/2 inches diameter.

The fitters were puzzled when I told them to stop flogging the bolts as we’d reached the calculated bolt tightness. They were used to a lot more Grunt & Sweat. So had been previously over tightening flanges. I never had a leaking joint under test.

So - torque alone is no guarantee of accuracy. Even-ness yes. But accuracy - No. It’s so dependent on the state of the thread. Lubrication and dirt are the main variables that means the effort applied will result in a “tightness” that may or may not be correct. As for Torque Wrench accuracy! It may have been accurate at the point of leaving the factory, but a few years down the line it can be significantly off the mark.

Anyone carried out a calibration of their torque wrench recently?

I’ll stick with tightening to ensure (a) staying tight and (b) not damaging the fastener or the item(s) being fastened.

Happy Torquing

Zitat von Boxerboy55 im Beitrag #31

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A slight digression ….

Back in the 80s I was a young engineer on a petrochemical plant directing fitters who were flange tightening on large heat exchangers and reactors using ultrasonic bolt tensioning equipment. I was measuring bolt stretch on large diameter bolts up to 2.1/2 inches diameter.

The fitters were puzzled when I told them to stop flogging the bolts as we’d reached the calculated bolt tightness. They were used to a lot more Grunt & Sweat. So had been previously over tightening flanges. I never had a leaking joint under test.

So - torque alone is no guarantee of accuracy. Even-ness yes. But accuracy - No. It’s so dependent on the state of the thread. Lubrication and dirt are the main variables that means the effort applied will result in a “tightness” that may or may not be correct. As for Torque Wrench accuracy! It may have been accurate at the point of leaving the factory, but a few years down the line it can be significantly off the mark.

Anyone carried out a calibration of their torque wrench recently?

I’ll stick with tightening to ensure (a) staying tight and (b) not damaging the fastener or the item(s) being fastened.

Happy Torquing

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Zitat von Boxerboy55 im Beitrag #31

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I’ll stick with tightening to ensure (a) staying tight and (b) not damaging the fastener or the item(s) being fastened.

Happy Torquing

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