NPT thread mills come in straight, helical and staggered tooth design. They will cut both internal and external threads. NPTF are for dryseal applications.
NPT / NPTF
Stub Acme Internal SPTM Thread Mills
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
Metric Straight Flute Thread Mills - Solid Carbide - Full Profile