Making tapered threads in brass, aluminum, or other difficult-to-roll materials is challenging. Attachment "walking" or "screw jacking" during cold forming result in flaking, slivering, and poor thread finish.
The match taper uses skewed rolls so that the large diameter of the thread roll works the large diameter of the workpiece, and the small diameter of the thread roll works the small diameter of the workpiece. Match taper more accurately tracks the roll on the part to reduce roll slippage and thread-roll wear.
C.J. Winter Machine Works Inc., (A), 130 Albert St., Rochester, NY 14606-5594; (800) 288-7655 Ext. 500.