Calculate all the possible gear combinations for the gear selector to cut a 15TPI thread:
Imperial TPI C 5 24 20
Imperial TPI C 1 24 30
Imperial TPI B 1 24 60
Imperial TPI A 6 24 70
Imperial TPI B 1 28 70
Imperial TPI C 5 36 30
Imperial TPI B 5 36 60
Imperial TPI B 5 42 70
Imperial TPI C 1 48 60
Imperial TPI B 6 48 70
Imperial TPI C 1 56 70
