Torque Wrench Calibration

wrote in message
...
I was getting ready to install a replacement manifold on the old Mercury
and it occurred to me I ought to be pretty sure my torque wrench didn't
strip the aluminum threads. The Snap On dial wrench hasn't been
recalibrated for 30 years and the Craftsman torsion bar wrench is too
clumsy to get to some of the bolts. I was kicking it around and I came
up with using the torsion bar wrench on a bicycle axle nut and then
putting the dial wrench on it to see if the reading matched. It did.
Then, I went ahead and checked the Craftsman clicker wrench of the same
vintage and recalibrating, and it came up with a match also. Then I did
the torquing with the dial wrench and cross checked it with the torsion
bar wrench, with all good readings. So, I'm just going to call them
calibrated.
Andy
Phoenix


You might check around for a lab. A phone call to these guys indicate rates
of $35 to $55.
http://www.teamtorque.com/index.html

wrote in message
...
I was getting ready to install a replacement manifold on the old Mercury
and it occurred to me I ought to be pretty sure my torque wrench didn't
strip the aluminum threads. The Snap On dial wrench hasn't been
recalibrated for 30 years and the Craftsman torsion bar wrench is too
clumsy to get to some of the bolts. I was kicking it around and I came
up with using the torsion bar wrench on a bicycle axle nut and then
putting the dial wrench on it to see if the reading matched. It did.
Then, I went ahead and checked the Craftsman clicker wrench of the same
vintage and recalibrating, and it came up with a match also. Then I did
the torquing with the dial wrench and cross checked it with the torsion
bar wrench, with all good readings. So, I'm just going to call them
calibrated.
Andy
Phoenix

Calibration can be like measuring with a micrometer and cutting with an axe.
Unbrako says that torque wrench accuracy for generating the clamping force
is +/- 25%.
For a 100 in-# set click you could be providing 75 or 125in-# instead. How
close a calibration to "truth" is needed?

Stu

On Jun 29, 10:20*am, "Stu Fields" wrote:

Calibration can be like measuring with a micrometer and cutting with an axe.
Unbrako says that torque wrench accuracy for generating the clamping force
is +/- 25%.
Stu

True, clamping force and "torque" are not always a direct
relationship. Thus the use of Torque-n-Turn specs (and other methods
of overcoming thread friction). I've never seen any specs for AN
hardware other than simple torque values. Do Torque-n-Turn specs
exist for AN hardware? Yes, I know that AN hardware isn't "torque to
yield" but the method is still of value for reusable fasteners.
=================
Leon McAtee