Tools & Gear Taps & Dies HSS Hand and Machine Taps

3086-1/2I 1/2" x 12 Left Hand BSW Intermediate HSS Tap HSS BSW LEFT HAND Intermediate Hand and Machine Tap. British Standard Whitworth has a thread angle of 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. Manufactured from HSS this general purpose tap is designed for use in medium tensile materials and is for hand or general machine use.