Forming the relief of the tap
The thread profiles of the taps are not usually ground round, but are instead provided with a relief grinding.
The relief is a free grinding which, depending on the design, can extend over the entire thread profile or is introduced with a round grinding chamfer width or is only carried out in the flank and core diameter. The undercut facilitates free cutting during the machining process, since not the entire thread profile rubs against the workpiece, but only the cylindrical grinding phase. A further so-called relief is located at the tap cut (chamfer relief).