[Skytrooper]

As far as calibration goes, as long as you are not using them on aircaft, not too much to worry about.

REMEMBER... always wind them back down to zero when done using them. They use a spring to control when they "break away" upon reaching the torque setting. Leaving tension on the spring is the quickest, easiest way to turn them into a breaker bar.

When a torque wrench is calibrated, they adjust or replace the spring.