Re: Bolts r' us

[paul.heneghan@bbc.co.uk (Heneghan,Paul)]

From: Psycho Bob <honge@creighton.edu>

>Come to think of it, do I need to get my torque wrench calibrated? This is
>the kind with the head that "clicks" when the right torque is applied. The
>torque value is set by turning the handle. I got mine at Sears...

I used my torque wrench for nearly 10 years before I bothered to check 
 its calibration and it was about 10% out.  

One way to check it is to get a heavy object like a large car battery.  
 Weigh it on a (digital) bathroom scales; weight = W.  Attach a 17mm 
 socket to the TW.  Attach a 17mm hex (gearbox drain) drive to a 
 standard ratchet/t-bar of length L, and connect the socket to the hex drive.

Place one edge (one of the narrow edges) of the battery on a piece of 
 wood.  Put the tip of the ratchet/t-bar handle under the opposite 
 edge.  If the battery is resting on two opposite edges, the force 
 exerted on each edge by the battery is W/2.  Therefore the torque 
 setting required to lift one edge of the battery slightly off the 
 ground is L x W/2 (assuming even weight distribution in the battery - 
 turn the battery around and average the readings if this worries you).

The clicking TWs that I have seen can be callibrated with an Allen key 
 adjuster.

I've just read back through all of this and it is about as clear as 
 mud, but it worked for me.

Paul
paul.heneghan@bbc.co.uk
1984 Audi 80 quattro
1983 Audi 100 Avant