Cycle thread taps & dies

[mklotz]

The magic ratio relating metric and inferial is 1.27. (The prime factors of 254 are 2 and 127). While a 127 tooth gear is doable, it's generally very unwieldy for the averge banjo. Approximations are in order.

Using my GEARFIND program, the simplest two gear approximation is:

47:37 = 1.27027... with an error on the order of 0.02%

If willing to go to a four gear set...

30:23 - 37:38 = 1.27002... with an error on the order of 0.002%

Using gears with larger numbers of teeth can produce better approximations but I've searched for small tooth count sets to keep them of reasonable diameter. You're free to download the program and explore it more fully if desired.