hob with hinterschliff

摘要

There is a tap whose thread portion 2 forms a cutting section 5 and a guiding section 6 and is provided on a plurality of adjacent thread teeth of the cutting section 5 with a relief 8. It is desirable that a further machining measure be provided for the tap whereby favorable compromises can be obtained with respect to guidance and friction. This is achieved in that the relief 8 of the adjacent cutting- section 5 thread teeth--seen in a longitudinal direction--have a clearance angle which varies increasingly or decreasingly. Varying the relief enables the requirements with respect to avoiding incorrect tapping and avoiding friction- generated cold welding to be met and matched up in an improved manner.