How/where to get your torque wrench calibrated
#2
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I use to work at genentech, we had a tester in there that would tell you if the torque wrench was accurate. We had to send those units out for certification annually. I'm an instrument tech and calibrate all kinds of different things. Sometimes we have to send out equipment for calibrations that we don't have a standard for, usually it's not cheap, especially when you add shipping. If there is nothing more local, try teamtorque.com they offer nist cert if needed.
#6
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No juvenile jokes? I thought for a while and couldn't think of anything that could be jokingly said about calibration...
Anyways, lzykid, you said every 6-8 months? Do they de/un -calibrate that often? And by how much? We talkin a few lbs or like 10+? And how long is the down time to get recalibrated?
Anyways, lzykid, you said every 6-8 months? Do they de/un -calibrate that often? And by how much? We talkin a few lbs or like 10+? And how long is the down time to get recalibrated?
#7
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No juvenile jokes? I thought for a while and couldn't think of anything that could be jokingly said about calibration...
Anyways, lzykid, you said every 6-8 months? Do they de/un -calibrate that often? And by how much? We talkin a few lbs or like 10+? And how long is the down time to get recalibrated?
Anyways, lzykid, you said every 6-8 months? Do they de/un -calibrate that often? And by how much? We talkin a few lbs or like 10+? And how long is the down time to get recalibrated?
Calibration Frequency can be determined by the frequency of use; the often a tool is used, the more often it needs to be calibrated.
That being said, calibration costs money, but defective product costs more!
We'd start off doing a 3 month calibration period, extending it out by two month increments if the tool was found to be within calibration.
Some processes just ate up tools while others did not.
If you google "torque wrench calibration frequency", you'll get a lot of really good information.
FWIW, one of the finest torque wrenches made is the Proto-Stanley brand.
#9
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I gave my friend that works at Diablo Subaru my Snap On torque wrench, he said that the Snap On truck comes by every week to calibrate or whatever free of charge, I don't know how it works for other brands tho.
#10
If you don't need it to be an NIST traceable calibration, do it yourself. Just put the square drive of the wrench or an extension in your bench vice and hang a known weight off the handle. If you need it to be super precise this isn't going to cut it.
Let's say I'm interested in how accurate the wrench is at 25 ft-lbs. Measure the distance to the center of the handle to the square drive. Then calculate the weight you would need to hang off the handle to hit 25 ft-lbs. So lets says it's 18 inches to the handle so first convert the inches to feet:
18"/12"=1.5 ft
Then calculate the weight you need:
25lb/1.5=16.66 lb
Then hang 16 pounds off the handle and see what the torque wrench measures or whether it clicks. If it doesn't click after loading or clicks as are you are loading it, add or remove weight to arrive at the breaking point. Make sure that once the wrench is loaded, that the handle is close to horizontal, otherwise you'll be off.
Of course this isn't fast or super accurate. But if you're like me you just want to know that wrench is still in the ball park after sitting for years in your tool box, this is probably sufficient.
If you wanted to make this more precise you could factor in how much torque the weight of the wrench itself is adding to the measured torque. You could also measure the exact angle that the wrench is away from horizontal and using trig subtract the torque you are losing.
Let's say I'm interested in how accurate the wrench is at 25 ft-lbs. Measure the distance to the center of the handle to the square drive. Then calculate the weight you would need to hang off the handle to hit 25 ft-lbs. So lets says it's 18 inches to the handle so first convert the inches to feet:
18"/12"=1.5 ft
Then calculate the weight you need:
25lb/1.5=16.66 lb
Then hang 16 pounds off the handle and see what the torque wrench measures or whether it clicks. If it doesn't click after loading or clicks as are you are loading it, add or remove weight to arrive at the breaking point. Make sure that once the wrench is loaded, that the handle is close to horizontal, otherwise you'll be off.
Of course this isn't fast or super accurate. But if you're like me you just want to know that wrench is still in the ball park after sitting for years in your tool box, this is probably sufficient.
If you wanted to make this more precise you could factor in how much torque the weight of the wrench itself is adding to the measured torque. You could also measure the exact angle that the wrench is away from horizontal and using trig subtract the torque you are losing.
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