Tools & Gear Taps & Dies HSS-Co5 Machine Taps

3228-S1 7 Piece BSW Spiral Flute Tap Set 1/8-1/2" HSS-Co5 (Cobalt) BSW Spiral Flute machine tap set. Cobalt HSS taps are extremely hard and provide superior performance and increased tool life especially in stainless steel and high tensile steel. Spiral Flute taps are designed primarily for machine tapping of blind holes. They produce the best results in materials that produce long continuous chips. The right hand spiral forces the swarf out of the hole and prevents the chips from clogging at the bottom of the hole or in the flutes, which could cause tap breakage or spoiled threads. 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.