smkettner wrote:
Extension has ZERO effect on torque with a hand wrench.
Impact gun will be different.
Correct, As long as you are not "bouncing" on the wrench, the extension will have zero effect. Push-click-hold, the extension does wind up, but the torque on both ends of the extension is the same. If the torque was different on either end of the extension, something would be moving.
Its not usually a problem on 100 ftlbs, but I have seen guys trying to torque 6-700 ftlb by hand and they like to put a jumping motion into pulling on the wrench. This will create erratic readings.