Alpha HSS Tap Set MC-18x2.5 MCHS180Alpha 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.