A while back we had a discussion about torque loss and extensions. A question was left as to why impacts loose power when used with an extension. I've been trying to figure out a way to explain why. Here goes.First-impacts use internal weights or hammers to create the forces to tighten or loosen fastners
Second-think of the extension as a torsion bar.
Third-if you wind a torsion bar into coils you have a coil spring. Now, lets look at a coil spring as used in suspension for a bike. As the bike sits with no movement, or runs on a smooth surface, the tension of the spring holds the weight of the bike at a static height. When a wheel on the bike goes over a sharp bump the wheel moves up the same distance as the bump, but the end of the bike supported by the wheel only moves a little and thus smoothes out the ride. Why? Because the spring stored energy as it compressed while climbing the bump and then released the stored energy once over the bump. To put this back to the impact/extension problem.
The extension is the spring, the impact is the sharp bump, and the weight of the bike is the resistance to movement by the fastner.
Every time the hammers in the impact exert force on the fastner through the extension, the extension stores some of the energy and releases it between blows thus limiting the torque produced at the fastner.
My 2 bits. Good discussions! Garett.
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