Torque wrench types (was: Re: Tightening head bolts onenginestand?)

[gforbess at attglobal.net (Gordon Forbess)]

On Wed, 4 Feb 2004 18:20:06 -0800, "L F" <rocco16v@netzero.net> wrote:

>  Yes, the clickers should be calibrated, but unless you use this type =
>on a daily basis (and how many of us do?), an annual calibration is =
>sufficient....and good peace-of-mind that's worth the cost.

I was a nuclear weapons technician in the Army and we also were
responsible for calibrating torque wrenches as well as the electronic
test equipment.  Our calibration interval was only 90 days.. a bit of
overkill to be sure, but I can't EVER remember actually changing the
calibration of a clicker wrench.  They just didn't vary.  OTOH, if a
beam indicator wrench went out of spec, it was simply discarded, and
that happened.  Our equipment was also checked by mobile "calibration
teams" every six months for accuracy.  These guys had their stuff
checked by the Bureau of Standards on a regular basis.  I'll bet the
US Government had torque wrenches worth thousands of $$$.

The main point to remember with torque wrenches is to use the correct
one.  If you need to torque to 100 lb/ft, use a wrench that goes 0-125
0r 150 lb/ft.  Don't use this wrench for a bolt that needs only 25
lb/ft.  Torque wrenches are most accurate in the middle third of their
range, regardless of type.

Gordon

75 Mk I/Drake 1.9
http://pws.prserv.net/gforbess/scirocco/scirocco.htm