[yelcab1]

First, about calibration: I use the at home calibration method. with only one modification. I open up the handle and adjust the mechanism so that the wrench clicks at the right value.

Second, about torque-ing: I always had the clicker type and torque the fastener until it clicks and consider it done. Never had any problems even with head nuts. Then I just bought a new electronic torque wrench that you can digitally select the value, and it will continuously measure the applied torque all the way to the final torque value as you finish the torque. In almost every single time I use this new wrench, the ending torque is 20-30% higher than what I set out to do. So, I have always applied 20-30% more torque than I really needed and still never had any problem.

Lesson learned: for critical fasteners (head nuts), go slow and approach the final values carefully, and stop just as it clicks.

Criticism: if I had always torqued 20-30% higher than the value I need, and still never had an ounce of problem, then what good is calibrating a wrench to 3% of its value?