Got in some new tools, a digital torque gauge, spring compressor, borescope, donated torque wrenches
Used the digital torque gauge to test the calibration (at least the piece of paper that came with the new gauge claims it’s within .5 %), the old 1/2" torque wrench seemed to be nearly 10% off, reading 91 ft lbs instead of the 100 it was set at. The replacement was within 2-3%, manufacturer claims within 4% I think. It is surprising how much variability there is in each pull, you have to be very consistent and stop at exactly when it starts to click.
Since the old one was off we decided to take it apart before throwing it away (these are not quality torque wrenches)
Interesting to see how it works, The tapered piece of metal is what is connected to the head of the ratchet, the body of the torque wrench pivots at the head, and the only thing that keeps the tapered shaft centered is the pressure from the spring through a little cube of metal. When enough torque is applied the little cube tilts over enough so the small tapered piece hits the body.