Does a beam type Torque wrench ever lose its calibration?

[Chris142]

Does that make sense? I got some new tires on the Jeep today and they used the impact gun to put the wheels on.

I want to loosen the lugs here at home and make sure that they are torqued to the specs-----> 90-105 ft lbs so I can change a tire on the road if I have to.

My good clicker torque wrench is locked up at work. I do have a beam type here at home that has to be 50 yrs old!

I'm thinking that yes the beam type is not quite as accurate as the clicker it should be ok....Definatly better than just hammering the lugs on like they did.

IMHO + or - 5 to 7 lbs won't really matter on the Jeep lugs.

Any reason not to do this?

 

[oilyriser]

You could always measure the old wrench's calibration using a weight scale and a tape measure. Measure the distance, in feet, between the center of the handle and where you put the socket. Put the wrench on a lug nut, and pull using the scale, from the middle of the handle, perpendicular to the bar. This will give the number of pounds you're pulling on the handle, while the tape measure will tell you the number of feet. Multiply the feet by the pounds, and see if the scale on the torque wrench agrees.

 

[Al]

Torquing wheels even with perfect calibration gives uneven tensiou bc of the very high friction between the lug and wheel. Not worth the time and effort. If you can put a consistant force with a breaker bar..with a little experience you are just as well off.

 

[ebaker]

As long as the pointer zeroes OK it should be fine, probably more accurate than a high quality clicker type.

 

[tom slick]

the USAF considers beam type torque wrenches lifetime cal'd as long as they aren't abused or dropped. clicker type are calibrated every 6 months.

 

[Chris142]

I went ahead and loosend every lug then tightened it as close as I could get with the beam type wrench.

Some were pretty tight!

I'm more comfortable now knowing that I personally checked every nut and they are reasonably close to specs

 

[rpn453]

quote:

---

Originally posted by Al:
Torquing wheels even with perfect calibration gives uneven tensiou bc of the very high friction between the lug and wheel. Not worth the time and effort. If you can put a consistant force with a breaker bar..with a little experience you are just as well off.

---

Does this happen even if you follow a proper torque sequence and do them all 3 or 4 times before reaching full torque?

Steel's modulus of elasticity will not change over time so, unless it's been damaged, the torque wrench will be as accurate as when it was purchased.

 

[oilyriser]

When I first installed my winter tires with new steel rims, I noticed that some of the lug nuts would loosen again a couple of weeks after I tightened them. After a couple of tightenings, they stayed tight.

 

[Al]

The force you apply is used up in streatching the bold (which actually applied the clamping force) and Friction between the nut/washer and the bolting surface and also thread friction. Even in a well lubricated bolt/nut with the lub on the threads and mut face, well over 50% of the torque is gobbled up in friction. I'm willing to bet on a wheel lug (with no lub) 75% of the torque goes into friction. So any irrregularity makes a huge difference in clamping force.

I'm not advicating not torquing but its not at all that precise.(IMHO) And yes I go around the wheel probably a half dozen times to get them all "feeling" the same.