Steven J. Richardson rote, 1/22/96: <<There are also two different types of friction which act in the system--the static friction before the key is set in motion and the friction when the parts are moving. (Static friction is larger than rolling/slipping friction.)>> Yup, the old static and dynamic friction. That's why when I place my gram weights on the key front, what I want is not the weight which when finally released on the key comes immediately out of the starting gate and having made it out, trots quickly through the key's stroke. This is the weight which easily overcomes the static friction (which is always higher than the dynamic friction). That friction barrier might amount to no more than 2% of the time and distance of the key's stroke. I'm interested in the other 98% of the stroke, during which the friction you encounter is dynamic. To make sure that I'm drawing within a gram of the dynamic friction I like to see the weight which can't break free of the static friction's grip without a bump on the action frame, and which when into the dynamic friction moves at the slowest possible motion, just short of stalling. Frequently, the dynamic friction make vary as much as two grams throughout the stroke. This is the friction gradient. Sorry folks, it comes with the territory. At least, it never gets more than 2g. Think of this. Cover the tip of your finger with a bandaid so that your fingertip is insulated from direct tactile contact, close your eyes and have a friend gently place a 2g wafer on top of your bandaid. Can you detect that 2g? Not likely. Bill Ballard RPT NH Chapter, PTG "There are fifty ways to screw up on this job. If you can think of twenty of them, you're a genius......and you aint no genius" Mickey Rourke to William Hurt, in "Body Heat", discussing arson.
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