How accurate is rotary broaching?
Rotary broaching is a very accurate method of producing precision polygon forms in a variety of metal work pieces. Broaches are precision ground to insure accuracy, and the rotary broach holder is designed to help machinists make repeatable accurate forms on nearly all turning machines.
Rotary broach forms manufactured by Polygon Solutions are made to a standard +0/-.0005 inch tolerance. Hexagon and square broach part numbers include the dimension at the high side of the tolerance. Part #H02525A for example has a hexagon form, manufactured to 0.2525” +0/-.0005”.
The rotary broach holder is also designed with a small amount of endplay to help the broaching tool follow the pilot hole. Many machines are not exactly aligned, and it is not uncommon for the broach to be slightly off center for many machining operations. Polygon’s GT broach holder allows the broach to find its center in the chamfer, resulting in a very accurate broached hole.