Alpha HSS Hand Taps are precision manufactured in Europe to ISO529 standards. HSS Hand Taps are general purpose taps suitable for hand and machine operation, and are suitable for production use. 2N Tolerance for optimum thread fit that balances fastener performance, manufacturing, economy and convenience. Suitable for use in Steel, Aluminium, Copper, Brass etc. Always use lubricant. Alpha Tap Sets contain a Taper, Inter and Bottoming tap. TAPER taps have a lead of eight threads and are used as a starting tap in difficult or high precision holes. Alpha Taper taps can be identified by the single ring on the shaft near the driving square. INTERMEDIATE taps have a lead of four threads and are used in most general purpose applications. Alpha Intermediate taps can be identified by the two rings on the shaft near the driving square. BOTTOMING taps have a lead of two threads and are used when tapping blind holes. Usually preceded by a taper or intermediate tap. Alpha bottoming taps can be identified by their plain shaft, they have no rings on the shaft near the driving square. Details Item: Sheffield Unified National Coarse HSS Hand Taps Sub Brand: Alpha Quantity: Bulk 1 Pce - Supplied in plastic pack Bulk Tap set - Supplied 3 Tap Types per pack