Tools & Gear Taps & Dies HSS Hand and Machine Taps

C87YJC5 1" x 11.5 NPT Bottoming HSS Tap - Goliath HSS Bright Finish NPT Hand and Machine Bottoming Tap. Pipe taps are much shorter than a similar size of regular hand tap, but the design features are the same. Goliath HSS taps provide a high hardness to toughness ratio, compressive and tensile strength, good abrasion resistance and resistance to micro-chipping, ensuring a long tool life. Tapered Pipe Taps are used for tapered threading by hand or machine. National Pipe Tapered (NPT) is a US standard for tapered threads used to join pipes and fittings. The taper on NPT threads allows them to form a seal when torqued as the flanks of the threads compress against each other. However a clearance remains between the crests and roots of the threads, resulting in a leakage around this spiral. This means that NPT fittings must be made leak free with the aid of thread seal tape or a thread sealant compound. For each 12" increase in distance from the end, the diameter increases by 3/4". Bottoming Taps have a lead of two threads and are used to ensure minimum thread run-out when tapping to the bottom of a blind hole. Bottoming Taps are typically preceded by the use of a Taper or Intermediate Tap. Manufactured from HSS this general purpose tap is designed for use in medium tensile materials and is for hand or general machine use.