Sure-Grip expanding collet systems from Hardinge grip the internal diameter of a part for turning, milling, grinding, assembly, inspection and automation applications. They are designed to provide durability for long production runs, quality surface finishes and fast collet change-over from the front.
The expanding collet systems feature a one-piece body design that use exact-size, thru-hardened collet heads that can interchange with all assembly sizes from machine to machine. The collet heads have an under-over capacity of -0.001" to +0.015" (-0.025 to 0.38 mm) from their specified size to accommodate a range of part diameters. The collets are keyed for accurate, repeatable part positioning. The double-angle design offers true parallel gripping, in which the collet expands equally throughout its entire length rather than just at one end to maximize bearing contact against the part. This is said to result in greater stability and part accuracy. Parts are centered and located without adjustment. Higher rpms and feed rates produce more parts per hour. The expanding collet system also features a built-in safety stop to prevent over-expansion.
During chucking operations, parts can be located against the face of the arbor or against a machineable workstop. This provides exact part-length control as well as improved part consistency. The expanding collet draws the part firmly against the stop for a stable part location, making it well-suited for longer parts, the company says.