Tools & Gear Taps & Dies Chrome Alloy Taps

BSWBRITISH STANDARD WHITWORTH The angle of thread is 55 degrees as opposed to 60 degrees in Metric and Unified threads. This thread form was developed by Sir Joseph Whitworth in 1841. The thread form has rounded roots and crests and is specified in BS84:1956. INTERMEDIATE TAPS have a lead of four threads and are used in most general purpose applications to cut a thread true to a pre-drilled pilot hole.