6G-1/2" HSS-Co5 (Cobalt) UNC Spiral Point (Gun Nose) machine tap set with HSS tapping drills.
Cobalt HSS taps are extremely hard and provide superior performance and increased tool life especially in stainless steel and high tensile steel.
Gun nose taps have straight flutes supplemented by angular cutting faces at the lead.
The design of the cutting portion propels the swarf ahead of the tap leaving the flutes clear for the flow of coolant to the cutting teeth.
Primarily designed for use in through holes, these taps can be used in blind holes provided that there is ample clearance beyond the threaded section to accommodate the swarf.
The advantages of a gun nose tap are the shearing action of the angular cutting faces, which produces a fine finish on the threads and shallower flutes. This allows a stronger cross section throughout the tap.
Unified National Coarse thread form was introduced in 1948 as an attempt to standardise thread forms in the USA, Canada and the UK.
The thread profile of UNC is the same as for metric threads and is described in the JIS B0206 standard.
The thread is described by its major diameter and the number of threads per inch of length (TPI).
This thread series is commonly used in the mass production of bolts, screws and nuts.
It is used for threading into lower tensile strength materials (bronze, brass, aluminium and plastics) to obtain the best resistance to stripping of the internal thread.
It is also used on quick assembly or disassembly or if corrosion or slight damage is possible.