I hope you didn't take my explanation to mean that you somehow mark the path a knot in a string takes! I figured you would get the physical explanation and then draw the curve in your CAD package perhaps using a 3 point curve.
An constant point on a line that is always tangent to a circle (the base circle) as the line is being swept around the circle (as if unreeling a string), IS THE DEFINITION of an involute. There's probably a nice mathematical definiton out there? Standard gear cutters are approximations of this shape, and as long as there's reasonable gear lash the inaccuracy doesn't matter much, but pauluk makes it sound as if he's going to either grind a cutter with data or mill the teeth with data. |