Round Dies are chamfered on both faces. Adjustment is obtained by a fine pitch screw which forces the sides of the die apart, or allows them to spring together.For threading, a High Speed Steel Round Adjustable Die is desired for improved wear life. #4-36 13/16" OD HSS Round Adjustable Die 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.