The 15° helical flute thread mills are non-crest cutting for internal threads only. The helical flute distributes the side cutting pressure.
15° Helical Flute - Metric
Stub Acme Internal SPTM Thread Mills
Acme Internal SPTM Thread Mills
Metric 30 degree Helical Flute Thread Mills - Solid Carbide - Full Profile
Metric Straight Flute Thread Mills - Solid Carbide - Full Profile
BSPP / BSPT Thread Mills - Straight Flute