torque extension bars ???

[bonnie john]

hi, anybody use these?

they are the socket extension bars used on air wrenches to tighten bolts etc to a pre determined torque setting. they use different colors for different values

i want to know how accurate they are and would love to find out HOW THEY WORK. so far, i have only heard that tire places use them to get the right torque on lug nuts

thanx in advance, johnny

 

[Merkava_4]

Quote:

---

i want to know how accurate they are and would love to find out HOW THEY WORK.

---

When their rated torque is applied to them they will start to twist; therefore rather than transferring the torque to the lug nut, they will begin to absorb the torque. Each colour coded extension will twist at a different torque setting. This is done by some kind of metallurgical programming that determines when they begin to twist and limit the applied torque.

As far as how accurate they are? I don't have an answer for that.

 

[alreadygone]

Have never bought them for my tire shop because to be accurate, impact must be run through a pressure regulator at a specific pressure setting (90psi I believe) .

Bob

 

[punisher]

It just has to do with the diameter of the "stick". The thinner sticks torque to a lower figure than the thicker ones. Our shop gave each tech a set of 4 (80lb, 2 100 lb, 140lb) and we tested the heck out of them because we couldn't figure out the physics of them. THe sticks worked as advertised, with 140psi of shop air pressure, and all kinds of different impacts. Once the lugnut gets to a certain torque the stick absorbs any further input. Obviously it only works with impacts. I have no idea about the quality/accuracy of the cheapie sets sold now.

 

[Ramjet Roger]

I've have purchased a set (I think they were called Acutork) for use on lug nuts. I used to be paranoid that they were ---- and always followed up with a torque wrench just to make sure. After a few years of this, I abandoned the torque wrench since the torque sticks were just as accurate. Must lug nuts have an acceptable range of 10-20 ft/lbs. So even if the torque stick is off a bit, it's plenty good enough. The critical point of torquing lug nuts is to ensure even torque across all the lugs on the wheel. Torque sticks do that and they accurate as well. BTW, I always run my impact wrench at 120 psi. I verified that the same torque setting was achieved at both 90 and 120 psi.

 

[bonnie john]

cool, t/y guys

 

[mechtech2]

Even some tire joints follow up with a torque wrench.
These are not really worth it if you are not doing tire changes for a living.

 

[Merkava_4]

I still don't have a foot pound torque wrench, so I'm still bolting the wheels on with a long 1/2 drive flex-head ratchet. Supposedly it's 17 21/32" long; although I've never measured it. I think I put on a 3 inch extension and a deep socket. I just give it all my mite until I can't turn them anymore; I'm not recommending that as the right way though.