Torque wrench miscalibrated

[21121956]

Hello everybody:

When a torque wrench is miscalibrated, let us say in 20 N.m, is it technically accepted to add/to diminish that amount to the required torque value at the time of using it?

 

[rb1957]

i'd express it differently ... your torque wrench has a calibration curve with a non-zero intercept ... so long as you have a calibration curve, that shows the relationship between the torque indicated and the torque applied, then you're ok (ish) ...

 

[MintJulep]

"Calibration" is establishing a known relationship between the setting of a knob or value on an indicator and the actual quantity being produced or measured.

Ideally, the relationship is equality, but that is not a necessity.

So, if you know what to set the dial to in order to get what you want then yes, that is "technically accepted".

I would not trust the average technician to do this correctly, and would not allow it on anything that I was paying for.

 

[btrueblood]

The "ish" part is in not knowing why the offset is there; was the part subjected to a one-time overload, or has some internal part worn over time...

If the latter, then how do you know it's not still wearing, and the offset not shifting further? Answer: recalibrate again...and what do you do about the assembly shipped after calibrating last week, when the calibration is unacceptably shifted this week...