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.
Diameter: 12mm
Pitch: 1.75mm
Overall length: 75mm
Shaft Diameter: 9mm
Drive Square: 7mm
Tapping Drill Size: 10.20mm