Calibrating torque wrenches, was dist. rattle

[auditude at cox.net]

Bernie,

Well, maybe we're used to different terms.  To me, when something is calibrated, it is reset 
against the standard.  Something is changed to bring it within the tolerances.  

Like with some video cameras you do some kind of calibration setup against something 
white before you use it (don't know if that's current technology).  Or when I look down at the 
bathroom scale with nothing on it and it shows 4 pounds, when I reset it to zero before using 
it, to me that is calibrating the scale in a way.  This is different to me than putting on a 5 
pound weight to verify that it measures 5 pounds, and therefore requiring no adjustment at 
all.  The words I use in that instance is a calibration check, altho' I'm not asserting that it is 
the correct or best term to use.

Altho' it's not necessarily a technical definition, we can look to trusty dictionary.com to see if 
it helps.

http://dictionary.reference.com/search?q=calibrate

cal·i·brate     P   Pronunciation Key  (kl-brt)
tr.v. cal·i·brat·ed, cal·i·brat·ing, cal·i·brates 
1. To check, adjust, or determine by comparison with a standard (the graduations of a 
quantitative measuring instrument): calibrate a thermometer. 
2. To determine the caliber of (a tube).
3. To make corrections in; adjust: calibrated the polling procedures to ensure objectivity.

I'm using either the "adjust" portion of definition 1. or definition 3.  It sounds like you are 
referring to just the "checking/determination" portion of definition 1.

Or maybe you are using the same definition as I am, but you haven't yet described what you 
Do Yourself when the wrench doesn't repeat the correction measurement against the 
standard?  I guess with a pointer style you can maybe bend the pointer, but with a click type 
I wouldn't know what to do.

If the report that came back with my torque wrench showed that it was as effective when I 
got it back as it was when I dropped it off, then for sure I wouldn't think it was worth the 
money.  But since they changed something in it or about it to make it more effective, and I 
don't yet know how to Do That Myself, I figure it was worth it.

Cheers,

Ken

On 27 Jan 2004 at 19:38, Bernie Benz wrote:

> 
> > From: auditude at cox.net
> > 
> > Is there a DIY calibration, versus calibration checking?
> > 
> > Ken,
> 
> What's the diff, Ken?  A check or calibration is only a repeatability check
> on the previous calibration.  I do it before every use (once every 2 or 3
> years, if I need the wrench and can find it).  DYI is pretty simple.
> Torque = force x the quadature lever arm length.
> 
> Bernie 
>