Alpha Carbon Hand Taps are precision manufactured in Europe to ISO529 standards. Carbon 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. Click here for our range. 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. Diameter: 5/16mm Pitch: 18mm Overall length: 53mm Shaft Diameter: 6mm Drive Square: 4.9mm Tapping Drill Size: 6.60mm