torque value foir compression fittings

[pattimelt]

I am having trouble on grease lines blowing. There is a torque value for the compression fittings that we cannot obtain from the European manufacturer (Dropsa). These are 26mm fittings and they just are not compressing. Manufacturer will not return any phone calls or emails at all. Can anyone assist with a torque value for these bad boys?

 

[unclesyd]

I would verify your threads and see if you could find a value for a comparable fitting from a different manufacturer. A lot of lubrication equipment has cross references for compatibility.

 

[Duwe6]

If nothing else works, switch to a better fitting system like Swagelok. Have seen a 101,000 psi rupture test on 1" swagelok; tubing failed, fittings held.

 

[ports394]

Duwe6, late post... but holy! 101,000 psi.

Pattimelt, I've never used a torque stick on the compression fittings. What kind of tubing are you using? I've seen some people try to put compression fittings on regular pipe...and you have to torque the hell out of it to get it to grab at all.

 

[pattimelt]

I think my problem is occurring from the fact that it is metric items and we are trying to torque to a different value. Haven't heard any problems of late but that might just mean they aren['t reporting any problems.

 

[danw2]

For what it's worth:

Back when I was involved with high pressure 'engineered' fittings (the steel and stainless steel ferruled fittings, not brass compression fittings) the manufacturer's installation procedure did not use a torque wrench. The nuts were tightened by hand finger tight, until there was no axial or radial play/movement. Then the nut was wrench rotated X.Y turns, 1 1/4 turns for 1" tubing, 3/4 turns for tubing < 1".

"In fact, Swagelock specifically advised against measuring torque:Measuring torque requied to pull-up a SWAGELOCK Tube Fitting is not a reliable measure of pull-up. All the tolerances of precise O.D., ovality, wall thickness and hardness of the tubing will vary the torque required for full pull-up. Pull-up can be checked wtih a Gap Inspection Gage." (Swagelock's Tube Fitting and Installation Manual).