Hand Tools

you just measured static coefficient
Response To:
Speaking of which, Bill, ()

Bill Tindall, E.Tn.
Static coefficient of friction is simply the tangent of the angle of an inclined plane where the object begins to move. All the multitude of variables cancel in this experiment to yield the simple result. It is a delightful observation to watch the variables go away from the derivation and be left with Tan (angle).

Contact area is not a variable unless there is deformation of one of the objects sliding. So we need another explanation for dull vs shiny. Maybe it has lapping grits embedded.

My bold previous statement that if anything we want to increase friction is likely flawed. I am struggling through a static analysis of forces on the cap iron and in turn the useful force on the shaving. Every time I think I have it right I find an error. But, I think I will eventually prove that substantially more friction force is wasted in the orthogonal to the wood surface (Y) direction than the pushing force from the cap iron along the axis of the wood (X). Hence, it will be more efficient to get the force on the shaving from the angle of the cap iron and not from increasing friction of the shaving on the cap iron. David wins after all ;)

My neighbor is a brilliant mechanical engineer. I need to get him engaged in this problem.

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