Power tool for bolt torquing 1

[JoJoBlue]

I'm currently running tests on CPVC flanges. The assembly requires the flanges be assembled with a rubber gasket inbetween and 8x 5/8 nuts and bolts per set. The bolts are tightened in a cross pattern, torqued in steps of 20, 40, 80 and 110 ft-lbs. I have had 20 tests done so far using a torque wrench, but I'm finding that the torquing of the bolts is taking up too much time and energy. There are at least 50 more tests scheduled in the short-term and regular inspection tests in the long-term (some of the QC technicians are significantly weaker than me).

So far, I have tried a pneumatic impact gun I borrowed form the floor, but I could not set a specific torque (I had a 0-5 dial) and it has been damaging the nuts and bolts (for this size/grade, they're kind of expensive, so reusing would be nice). I have also been looking at pnuematic nut runners, but have not found one with a high enough torque to be of any use. I am wondering if anyone knows of any power tools that can be used to torque bolts to 20, 40, 80 and 110 ft-lbs (or maybe +/- 5 ft-lbs) without destroying the nuts and bolts after each use? Thanks!

 

[MikeHalloran]

The auto industry uses multiple spindle torque controlled nutrunners that would speed the work, but you may be sticker- shocked.

I found a fair number of electronic torque wrenches for sale. I couldn't find an indication that they were, or were not, adaptable to doing torque steps without a lot of screwing around, but many of them can be had with computer links for verification.

It occurs that you could do torque steps with fixed clicker torque wrenches by inserting a series of torque multiplier adapters, one at a time, or by coming up with a torque multiplier bar that telescopes stepwise. I haven't seen such a thing for sale, so it would have to be homebrewed. It would have the virtue of offering increasing length and leverage at each torque step, so the tech wouldn't have to be unusually large.

Even something as simple as letting the techs work in teams of two or four might speed up the operation a bit.




Mike Halloran
Pembroke Pines, FL, USA

 

[CoryPad]

There are torque tools (e.g. electric nutrunner) and tension tools (e.g. hydraulic tensioner) that are used for work like this. They are expensive but accurate. Some potential suppliers include AtlasCopco, Stanley, Bosch for torque tools and HTI, Titan and Enerpac for tension tools.

 

[mcgyvr]

I've been looking hard for an on the fly adjustable torque tool.. Something with an electric clutch and tool mounted display screen with up/down buttons.. I don't think they exist.. So 4 tools would be your solution as adjusting the mechanical clutch requires #1 a torque calibration box and #2 adjusting internal "springs" to get the desired torque..

You will need solid torque arms too.. At those levels you will start breaking fingers/wrists,etc with a "powered" tool without them. For us anything over 75 in-lbs (yes in-lbs) with pneumatic tools gets a torque arm or the injury reports come flying in..

Like said above..prepare for sticker shock... Or really just forget it and continue with your manual torque wrench.. The ROI to invest in a powered solution will be VERY..VERY long.
I'd expect a min of $10k.. Heck just the small "production" electric screwdrivers (up to 16 in-lbs,etc..) are $600 to $1500 each..

 

[MintJulep]

Maybe a torque multiplier with a nut runner.

Some multipliers have a torque indicator dial.

 

[Benedictj1]

http://www.mountztorque.com

 

[checkline]

You can use an electric driver with a clutch to get close, then use a beam or click wrench to set the final torque for best accuracy. To check the output / clutch setting of the electric driver you can use a torque tester like this -> Link

Brett Linzer /

http://www.CheckLine.com

 

[JonSquared]

Try googling pneumatic torgue gun. We use a pneumatic (though you can go electric or hydraulic) that was purchased from

http://www.radtorque.com/.

With the pneumatic you have an air regulator that is dialed in via a gauge to the specific torque needed. with that low of torque your issue will be finding one that can be set as low as 20 and 40 ft/lbs at a reasonable price. Everything I found in our torque range had a price tag of about $5k. May be your only option is to do the 20 and 40 by hand then use a torgue gun for the last two steps. Also one last thought, if going with a pneumatic you need to consider it's power source, you need to make sure you have a compressor that has enough available CFM to keep a consistent pressure at the regulator for whichever pneumatic gun you were to go with or the torque will not be accurate.


Jon