| Author |
Message |
Ed Roelle (Ed_roelle)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 21, 2005 - 7:49 am: | |
I will communicate this on a couple of lists and share some information that I discovered about torque wrenches, after testing 5 wrenches.
The bottom line – be cautious if you depend on torques being to spec.
I found most of the torque wrenches were under-torqueing, from 15% to 30%. They were 3/8”, ½”, and a 3/4” clicker type torque wrenches from Harbor Freight, Craftsman, K-Tool, and Snap-On. (The Snap-On was the worst.)
For those of you interested in the technique, I clamped the square drive in a vise, and hung a set of weights at various distances from the drive. The wrenches were set and various torque levels, and the weights were moved farther out on the arm, until the wrench clicked.
I was able to adjust most of them with shims in the handle.. (Professional services charge $50-$75 to calibrate.)
Ed Roelle
Flint, MI |
Kyle Brandt (Kyle4501)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 21, 2005 - 7:56 am: | |
Hi Ed, Good idea. I've never taken the time to look into this, but how do you add shims? do you just uncsrew the handle knob & put the shims in there?
Thanks
kyle4501 |
Ed Roelle (Ed_roelle)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 21, 2005 - 8:05 am: | |
Kyle,
On the Craftsman, you remove the pin from the head, and carefully remove the mechanism. (Use a clean area because there are about a dozen small ball bearings.)
Most of the others, you remove the locking screw at the bottom to unscrew the handle. You need to overcome the feature on the screw, that prevents it from easily coming out.
Ed Roelle |
James Maxwell (Jmaxwell)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 21, 2005 - 10:29 am: | |
Not surprised, clicker types have always been known for not holding within tolerance, which I've seen variously spec'd from 1 or 2% up to 10. Yrs. ago, Proto made a rotary dial meter that was fairly accurate, usually within 1%, for checking them. Imagine how far off you could be using one that was 10% off thru a torque multiplier device that was 10% off. My Proto meter "walked off" many yrs. ago and I never could find another one. |
Pat Bartlett (Muddog16)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 21, 2005 - 6:21 pm: | |
In construction torque wrenches are calibrated each morning to insure they are correct, you would be surprised how much they change in just one day |
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