BSF thread

BSW thread

ISO inch thread

ISO metric thread

60 Degree

65 Degree

55 Degree

50 Degree

One

Two

Four

Three

To make internal threads in cylindrical jobs

To make external threads in cylindrical jobs

To make internal threads in square jobs

To make external threads in square jobs

No effect threads form normally

Threads forms unevenly

Both die and threads damaged

Pipe broken into pieces