Tech request: testing/calibrating a torque wrench...

I picked up a couple of torque wrench's recently. How do I check for functioning and can I home calibrate??

 

I kind of recalibrated a clicker that got loose, by using a 1/2" 8pt socket, and putting it on my beam torque wrench....I adjusted the bolt in the handle until it clicked when the beam wrench said I was at the torque the clicker was adjusted to.

or you could find a mac, matco, snapon, etc tool truck

 

I also checked mine by attaching them to a beam torque wrench and making sure they clicked when the beam said they should. You can also attach two clickers and they should both click at about the same time.

 

wow ,

after listening to you guys, i`ll stick with my beam type.

gary

 

Don't get me wrong, clickers are great, and it take a bit to get them way out of whack. The only way I'd stick with the beam is if they were cheap clickers like S&Ks or similar. As a rule for me, I won't buy a 1/2" clicker unless the retail value is $120 or higher. the ones that cost less than that I've had bad luck with. If yours are name brand, don't worry about it.

 

I think you can still buy a digital calibrating tool from Sears. Now that I think about it, I had heard that if it's Craftsman, you can take it in to Sears to be tested. But I could be completely and utterly wrong.

 

Do some checking by searching "torque wrench calibration" (type it in WITH the quotation marks) on Google. There's a wealth of information there.

Calibrating a torque wrench, or any gaging instrument, is not something you can really do at home and get accurate results. Lots of variables that can screw things up.

If you want accuracy, you'll need to send/take the torque wrench to a calibration shop that's certified traceable to the National Ins***ute of Standards and Technology (N.I.S.T.), which is the former National Bureau of Standards. N.I.S.T. is a government regulatory agency that sets the standards for calibration of all kinds of measuring instruments. I took my torque wrench in a couple of years ago and the price was nominal - as I recall, about $25.00. You can find these calibration shops all over and a list can be obtained by looking through Google. Torque wrenches are notoriously inacurrate and if you're depending on a beam or a clicker you just picked up at a swap meet or from Sears..........good luck!! I was in the machine tool business for many years and gage accuracy from many suppliers is pretty damn scary.

If "close" is good enough, go to H.F.

My 2¢

 

After watching a few old guys "torque" main cap bolts with an air impact wrench when I was young, I decided that maybe even if my torque wrench isn't calibrated within .01% accuracy, it's still a damn sight better than not using it!

btw, the one I "recalibrated" hardly ever gets used....I bought a new one to replace it before I fixed it.

 

How do you know the beam type wrench is accurate? They need to be checked too! Send the wrench out.

 

a beam type wrench, if it's made properly, will always be calibrated as long as the pointer returns to zero when it has no force applied to it.

 

torque= length of lever times force applied. should be easy to figure out with a spring scale.

 

Hey you pay shipping I can calibrate and cert your torque wrenches.
I am Quality inspector for the RailRoad and always have extra time.
Jimmy. Oh yeah I am also N.I.S.T Certified.

 

what's the price to calibrate it? - your going to have a lot of PM's if it is just "pay the shipping"

 

"torque= length of lever times force applied. should be easy to figure out with a spring scale."

Getting back to this basic definition...and away from the somewhat flawed accuracy of the average spring scale...I used to know a geezer who had a big nut welded to a column in his shop and a bucket weighted to about 75% of the scale range of his wrench. He simply put wrench onto nut and hung the bucket from the pivot point to see if wrench was accurate.
This obviously requires finding a scale more accurate than the one in the bathroom, but you only need it once. Doesn't a pint of water weigh just about exactly a pound?
And everyone seems to have a good opinion of the permanence of the calibration on beam wrenches. I remember reading an article by a Nascar engine builder who advocated using clickers only for things like cylinder head nuts, and doing the really critical fasteners, that is the rod and main caps, with an old beam wrench.