Is there a way to calibrate or at least check to see whether or not my torque wrench is accurate?

I have no special tools btw.

 

get another torque wrench and attach it to that torque wrench?

like the kind they sell at autozone with the little needle that moves...
just attach them with vicegrips or with a square piece of tubing?
and twist the dial one until the click one clicks... and take the reading?

 

r u asking me?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by david90 &raquo;</TD></TR><TR><TD CLASS="quote">Is there a way to calibrate or at least check to see whether or not my torque wrench is accurate? </TD></TR></TABLE>
Measure from the center of the square drive lug (where you put the socket) to someplace on the handle. If the handle has a hinge, that's the place. Get some weights, make sure you know accurately what they weigh.

Clamp the drive lug in a bench vise, handle horizontal. Read the scale, it might not be right at zero because of the weight of the wrench itself. Hang some weights from the handle, right at the place you measured. The torque reading should be the weight x the distance. Plus the tiny bit that you had before hanging the weight.

So...
Correct Torque = (weight x distance) + (small correction)
Compare that against what the wrench measures...

 

what about the weight of the torque wrench handle? Is that what u mean by "little weight before..."?

 

Yeah, the weight of the wrench itself will make it read some small torque, not quite zero, when you clamp it in the vise. The weights you add will add (weight x distance) onto that.

Or you could clamp the wrench vertically, then use a cord & pulley to hang the weights. Most likely, the weight of the wrench gives a really small torque that you can almost ignore.

 

so if I finds out that my tw is inaccurate, what can I do?

 

you can get them recalibrated. or at least the good ones you can. I'm pretty sure Griots garage offers the service. I'm sure it's not the cheapest place to get it done but it's the only one I know off the top of my head

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by david90 &raquo;</TD></TR><TR><TD CLASS="quote">so if I finds out that my tw is inaccurate, what can I do?</TD></TR></TABLE>
If you want to be totally **** about it, you could make up a table of wrench-readings vs. true torque. So for example if you want 50 lbf-ft you have to set your wrench for 45 or whatever...

I was gonna say 'it ain't rocket science', but actually it IS! That's exactly how calibration services work. If the device being calibrated doesn't have any internal adjustments to make it 'true', then they just make up a table of readings vs. true values. At work we've had torque wrenches calibrated by NIST exactly like that.