HFS toolholders have taper and face contact improving concentricity and changeover accuracy to less than three microns. The new toolholders evened out wear over all the teeth in the reamer, increasing tool life from 2,000 to 10,000 bores, and made it possible to reduce machining time by 15 percent by increasing cutting speeds and feeds. The connecting rods are made of carbon steel. The requirements for machining the smaller bore are a roundness of less than two microns and a cylindrical form within five microns. The machine's design has only one head, holder, and differential screw. The screw draws the taper in to make face contact, providing low runout because of the face contact. The roundness values and surface quality produces a contact area of up to 97 percent. Additional tool life improvements are provided by the high changeover and concentricity accuracy because the tool diameter can be adjusted closer to the upper tolerance limit. The coolant coverage of the toolholders provides further improvements such as the coolant outlet being only 0.27 in. behind the blade so the blades are flooded. The system is faster to change because all that needs done is turning the screw used to lock the tool in the opposite direction. This makes it easier to change the reamer head without removing it from the machine. The fact that all functions are activated with a single screw makes the toolholders easy to use.

Mapal