These straight flute thread mills have a 55° thread profile and cut the British Standard Pipe Parallel (BSPP) and the British Standard Pipe Taper (BSPT).
BSPP / BSPT
Stub Acme Internal SPTM Thread Mills
Metric Straight Flute Thread Mills - Solid Carbide - Full Profile
Acme Internal SPTM Thread Mills
Metric 30 degree Helical Flute Thread Mills - Solid Carbide - Full Profile
Metric 15 degree Helical Flute Thread Mills - Solid Carbide - Full Profile