several comments:
1. do not store the wrench until you zero the setting
2. do not drop the wrench
3. do not use the wrench as breaker bar

 

addendum:
4. do not use the wrench as a hammer
5. Never, ever add a piece of pipe to make the wrench longer. Ever.

 

In the manual for my sears wrench it says that you are only supposed to grip it where the grip is, wouldnt that make taking a block of would to the shaft potentially inaccurate or even bad for the wrench?

 

A. M.,

Twelve inches. Got it. At that length lever, the reading is correct.

Thanks.

R

 

After dealing with the calibration folks in the Army for twenty-five years, and after promising my Navy father-in-law that I'd be fair to sailors when I married his daughter, I'm choosing to believe A.M.

 

Can't say if it's bad for the wrench---that would depend on exactly which wrench it is (its mechanism/construction).

As for accuracy, it shouldn't matter. If you apply the force closer to the point of rotation, you will just need to apply more force, but the torque will be the same (more force but less length; product is the same).

 

Nope, no harm. And the closer the force is applied to the exact 12" point, the more accurate the reading. The Sears (and others) instructions are to insure that you apply the force to the correct point (the knurled part) rather than elsewhere on the handle to insure accuracy.
But, hey folks, it's a torque wrench. The accuracy of the reading changes with many factors: the condition of the threads -dry, oily, rusty, beat up, etc.- probably affects the reading more than anything else. The wrench will 'click' at it's setting, but the holding power of the bolt will not be the same as the next one you do. But it's close enough. No need to overthink it.

 

Sort of true, Ofioliti, but the wrenches are designed to operate correctly with force applied at a specific point. The beam/pointer type of torque wrench makes it easy to visualize: The wrench is calibrated for bend along the full length of the beam, going shorter leaves a portion of the beam unbent and the reading will be off. Same with 'click' type, but not as obvious.
Here, everything you ever (or never) wanted to know how they work:
http://www.tegger.com/hondafaq/torque_wrench/index.html
Edit: The 'dial type' wrenches don't care where you hold them, they're accurate no matter where you put your hand.

 

Ah, you are right. The bending does change things for reading.