Torque Wrench Calibration

Anyone have a good source for getting a professional quality torque wrench calibrated that doesn't cost a good chunk of what a new one costs?

The double beam ones hold their calibration quite a bit better than the click ones, and are calibrated to a tighter tolerance. Buying an inexpensive beam one to keep in a drawer and check your clickers against gets you most of the way.

If you find your equipment quite a bit out of cal the adjustment is usually in the handle end, something under a solder plug. It's just a spring preload adjustment, so it will shift the entire scale up or down, you'll need a new spring if you are in cal at one end and out at the other.

Use a load cell type torque cube. http://www.bargainoutfitters.com/net/cb/cb.aspx?a=550334

44Dwarf wrote: Use a load cell type torque cube. http://www.bargainoutfitters.com/net/cb/cb.aspx?a=550334

Calibration would still be unknown until it is tested. I think a lot of times people assume digital things are more accurate, which isn't always the case.

The digital will be very precise, but precision =/= accuracy. A beam wrench will always be fairly accurate(as accurate as the scale painted on it), as there is so much less to go wrong and its all visible(i.e. bent pointer). Good enough to keep a clicker calibrated close enough for hobby work.

Guys, I'm looking for a qualified place to calibrate my torque wrench.

Know any industrial engineers? Most big plants have their own tester.

Where my old man works everytime they send out a torque wrench for calibration it comes back non-calibratable and therefore junk. To test a torque wrench my father just gets one in calibration and torques the non-calibrated on against the calibrated one to see how far off they are. Good luck and let us know what you find out.

In reply to bravenrace:

You dropped it didn't you

You're in Akron? PM me for a spot in Seville/Lodi that you can test it at.

snap-on or mac will do there own brand recals but you would have to call your local rep to see if they will do other brands

benzbaronDaryn wrote: Where my old man works everytime they send out a torque wrench for calibration it comes back non-calibratable and therefore junk. To test a torque wrench my father just gets one in calibration and torques the non-calibrated on against the calibrated one to see how far off they are. Good luck and let us know what you find out.

So, the calibrated ones come back junk.

How does he know when he has one "in calibration" to test the non-calibrated ones against?

Bravenrace, I understand your question. I use to work in a chemical plant, and calibrating scales was always an issue. You can't package things accurately if you are not accurately calibrated, and they could loose calibration virtually anytime being bumped, etc.

I can't give you a referral. Here are a couple of shops in OH that might be able to help.

Tool calibration in Northern OH

Tool calibration in Southern OH

Good luck!

Apparently Bravenrace is the only guy here who read his user manual that came with his torque wrench which recommends recalibration every 2500 repetitions, or approximately once per year for most users.

I'm fortunate to work at a place where I can just take mine in and have the CMM dept. calibrate them.

Couldn't you stick the socket part in a vice, measure a foot out, hang some weights on it, see how close you are? Will that not work for some reason? J

Your local tool repair shop should be able to do it. The kind of place that repairs pneumatic and electric tools.

I picked up a nice old Proto 1/2" torque wrench and asked the tool repair shop to calibrate it. He said "sure thing, runs $80" I said "On second thought...." and picked up a $35 digital torque adapter he had on a rack. He just winked at me.

I understand that military bases usually have something on site. They are required to get them calibrated regularly. The snapon guys used to do it years ago.

Jcamper wrote: Couldn't you stick the socket part in a vice, measure a foot out, hang some weights on it, see how close you are? Will that not work for some reason? J

This seems reasonable if you have a "calibrated" weight and understand the error in your distance measurement. You would want to at least test the high end of the wrench and the low end. Some points inbetween wouldn't hurt either.

benzbaronDaryn wrote: Where my old man works everytime they send out a torque wrench for calibration it comes back non-calibratable and therefore junk. To test a torque wrench my father just gets one in calibration and torques the non-calibrated on against the calibrated one to see how far off they are. Good luck and let us know what you find out.

You can't test a torque wrench that way. Well, you can, but it won't tell you anything.

pappatho wrote:

Jcamper wrote: Couldn't you stick the socket part in a vice, measure a foot out, hang some weights on it, see how close you are? Will that not work for some reason? J

This seems reasonable if you have a "calibrated" weight and understand the error in your distance measurement. You would want to at least test the high end of the wrench and the low end. Some points inbetween wouldn't hurt either.

That would also work much better on a beam style than a click style wrench.

Throw the old one out and go buy one from harbour frieght?

As testing has shown in plenty of magazines, all new torque wrenches are calibrated decently from the factory. Getting yours recalibrated will cost more than it does to just buy a new one (probably), especially if you have to ship it anywhere.

Just food for thought, no different than that drill bit sharpening thread.

If it is professional quality contact the manufacturer or rep. Many will recalibrate it for free or for a small fee. As mentioned, MAC, Cornwell, Snap-On typically do this.

Me, I bought a beam wrench for $20 and check my SK Tools clicker against it every once in a while. According to that, the SK hasn't needed recalibration in the 15 years I've owned it. But I'm just a hobbyist user. I also always relieve the spring pressure when putting it away.

Just went out and tried the weights hanging on it a foot out. Clicker style craftsman. The torque wrench was about 4% off at 58 lb*ft setting. It would just barely click with 56 pounds gently hung from it. Wouldn't click at 59 lb setting. Easy peasy lemon squeezy.

Jcamper wrote: Just went out and tried the weights hanging on it a foot out. Clicker style craftsman. The torque wrench was about 4% off at 58 lb*ft setting. It would just barely click with 56 pounds gently hung from it. Wouldn't click at 59 lb setting. Easy peasy lemon squeezy.

This.

Good work.

I'm the quality manager at an ISO-17025 accredited lab, but we don't do torque, only plating and coating thickness. If you want to get technical, check out A2LA.org for accredited labs that do torque. (Probably $$ but guaranteed to be what you are looking for.)

I worked in a place that was calibration crazy. Wooden rulers, tape measures, the hashes on adjustable wrenches, everything.

We had paid some fancy lab to give us NIST traceable load cells on a fancy fixture for calibrating torque wrenches, which the techs were required to do every DAY.

I watched them sometimes. They would just keep trying until it worked. Going slightly faster or slower made all the difference. I had never heard of one being calibrated after being checked. Ever.

So, if you're close, I'd say don't bother. And I care about that stuff.