It is recommended over the straight-flute for more difficult materials, better surface requirements, and applications with an interruption such as a keyway or cross hole.
Adjustment is obtained by a fine pitch screw which forces the sides of the die apart, or allows them to spring together.The slot is beveled so that when the dies are used in a machine holder the adjusting screw can be removed and adjustment made by the adjusting screws in the holder Round Dies are chamfered on both faces.