The left-hand tapping hand tap set consists of three taps and enables you to cut a finished left-hand thread with significantly reduced risk of breakage. One left-hand thread is tapped counterclockwise. The left-hand tap or left-hand screw tap is also operated counterclockwise.
The advantage of three-piece hand taps is that the respective parts of a set share the cutting power: The taper tap (No. 1) (marked with one ring) removes 65 per cent of the thread profile and the intermediate tap (No. 2) (marked with two rings) removes 85 per cent. Pre-cutting and reworking with the intermediate tap (No. 2) bring the thread into shape. In the last step, the finishing tap (No. 3) is used, which has no ring marking. Only this cuts the full and usable thread at the end. The division of labour between the three screw tap makes it easier to cut a straight and clean thread by hand.
Compared to the machine tap, the hand tap has a short shank. This allows you to cut internal thread by hand without jamming and can be operated with tap wrenches, tool ratchets or other holding tools with square drive.
The thread can be cut in a pre-drilled core hole.
Due to the short chamfer of the finish tap, the hand tap set can be used reliably and universally for through holes and blind holes.
As a rule, three-piece hand taps- sets are used for regular threads with coarse pitch, as the thread profile area is larger than for fine threads and the force effects on the taps are greater.