My idea is converting two-radius-arc, side-profile, teeth-roughing hobs to trapezoidal profilers which have the same pitch. Using a computer program, I calculate teeth-profile radii for roughing and finishing hobs for straight and side-spline shafts, along with the necessary diameters in all standards — inch and metric, U.S. and European.
From the program, I developed tables showing that radius profile elements depend on O.D.s and the number of splines, especially for roughing hobs — the arc-radius sectors and their chord and rise segments. They increase when O.D.s and the number of splines increase.
With such information, I can grind and relieve radius profiles to trapezoidals from old or new radius hobs and make roughing trapezoidal-profile-teeth hobs for cutting straight-side spline shafts. As a precaution, I do test cuts before producing spline shafts.
North York, Ont.