I would like to make an involute gear cutter using the 2 button method as described by Ivan Law's book Gears and Gearcutting , p 114-.

No problem with the method, which is fully understood, but I need a 20 degree PA, No8 gear cutter for 12-13t. The book only gives the table of dimensions for cutters from No1 to No6. Can someone supply the remaining part of the table, or alternately define the equations which define these dimensions?

Possibly Ivan derived these best fit dimensions by drawing the actual involutes, in which case I will do the same, but a calculation method would be best. It is also possible that the deviation from the involute form becomes too great with the lower tooth counts and this is the reason why they are omitted.

Can anybody help?

No problem with the method, which is fully understood, but I need a 20 degree PA, No8 gear cutter for 12-13t. The book only gives the table of dimensions for cutters from No1 to No6. Can someone supply the remaining part of the table, or alternately define the equations which define these dimensions?

Possibly Ivan derived these best fit dimensions by drawing the actual involutes, in which case I will do the same, but a calculation method would be best. It is also possible that the deviation from the involute form becomes too great with the lower tooth counts and this is the reason why they are omitted.

Can anybody help?

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