Torque Wrench calibration

I have a Snap-On torque wrench that I've had for 35+ years and I know that it is out of calibration.
Calibration doesn't seem practical from a time or $$$ standpoint when you don't use the
wrench that often...

A couple methods I've used to try to get accurate torque are:

- for lug nuts in particular, before loosening, tighten w/the TW and adjust the setting
until it clicks and it just starts to turn the lug then use whatever setting the TW ends up at...

- put the TW drive into a vise, setting the handle parallel to the floor and hanging some old metal
free weights (90 lbs) I have on the handle, ajusting the setting until it clicks just as the weight is free
hanging. The first time I tried it, it seemed to work well. I did the same this weekend and it didn't click
until I had the dial @ 145-ish lbs but a couple hours later I hung the weights again came up with 75ish lbs....kinda blew my confidence in that method...
could the TW be changing that much / that short of a time frame?

All that to say, the question is, if you don't use a torque wrench often, how do you torque with
any accuracy w/out getting it calibrated every time?

oh man I feel stupid, when I did the hang the weights process I totally forgot about
doing the math formula for varince in TW length, so who knows what I ended up with

Noobz347 said:

It doesn't have to be calibrated every time. There is a maintenance interval.

Click to expand...

right... I didn't mean if you used it with short intervals between, I meant if it was
used infrequently enough that it might be out of calibration...

85GTStangGuy said:

Properly handled, stored and used, a torque wrench should be fairly accurate for a long time. That said, 3-1/2 decades is a long time.... that may be long enough for the spring inside to fatigue (assuming it's a mechanical, not a digital, wrench).

Don't know, but you may be able to use a digital torque adapter to roughly see the accuracy of your wrench.

Click to expand...

it is mechanical...
I thought of the adapter before but wondered if the same thing might occur with that...