Swiss-style Collets

A high quality collet is desirable when it comes to precision machining of small parts for the medical and aerospace industries. For a quality part that meets high-precision specifications, you need a burr-free collet with guaranteed concentricity. This collet would be finish ground to provide a smooth and concentric gripping area (order hole) for the bar stock or work piece. Hardinge Swiss-style collets meet all of these requirements. They are inspected on a Hardinge SUPER-PRECISION (.000015" TIR) headstock before reaching the stockroom.

Hardinge offers gripping solutions for producing small diameter parts for the medical and aerospace industries. Their products include headstock collets, pickoff collets, carbide guide bushings, bar loader collets and custom manufactured solutions.

"We've added several new collets and guide bushings to our inventory to meet customer demands and support newer machine models," states Rick Schonher, Product Manager for Hardinge Workholding Division. "Hardinge stocks standard headstock collets, extended-nose, emergency styles, pickoff collets and carbide guide bushings for most machine brands. We are also relied on for custom manufactured solutions for the Swiss-turning industry."

Keeping bar stock unmarked, holding a small diameter on center, holding a thin-wall part, ejecting parts and working with extruded bar shapes are common gripping dilemmas for the Swiss-turning industry. Hardinge has manufactured solutions for all of these problems. They can provide special accuracy order holes of .0005" or better for holding strict tolerances, as well as micro-inch finish order holes. They manufacture collets and guide bushings for D-shaped and other extruded stock shapes, along with pickoff collets with a built-in spring ejector that pushes the part into a basket or conveyor to automate the process. Hardinge has engineered pickoff collets for Citizen, Star, Tornos, Tsugami and other Swiss-type machine applications. Other special Swiss application collets include stepped, tapered, chamfered, radius and off-center order holes, and over-the-shoulder collets. Additional gripping dilemmas such as short gripping, non-marking, slippery materials, push back, tool clearance, multi-pass machining, large diameters and matched keyways are not a problem for Hardinge. Angular or zig-zag slotted collets hold hex or geometric shapes and keep chips and coolant from entering the spindle area.

Hardinge has partnered with Citizen Machinery America Inc. to produce adaptive guide bushings and overgrip collets to support the cost-conscious shop. The adaptive guide bushing allows the use of less expensive, non-ground bar stock. This system uses air pressure to open and close the guide bushing collet as the size of the material being machined changes. A kit from Citizen must be installed in the machine to permit the use of the adaptive guide bushing collet. Kits are available for new Citizen machine models and can also be retrofitted to some existing machines.

ID gripping pickoff collets may be the solution for parts with delicate outside threading or a thin wall and may eliminate the time and cost involved with second operations. Hardinge also manufactures bar loader collets for FMB, LNS and Robobar barfeeders. Other brand bar loader collets and Escomatic counter collets and guide bushings can be manufactured to order.

Hardinge stocks headstock collets, pickoff collets and guide bushings in many styles and sizes. Their standard round guide bushings are carbide-lined to keep the stock clean and unmarked. Hardened steel or Meehanite-lined bushings can be made for certain stock that is not compatible with carbide. Standard extended-nose headstock and emergency collets feature added nose length (straight or tapered) for doing pickoff work or to compensate for tooling interference. Emergency collets are handy to have in your tool drawer and can be machined to the desired bore size right in your shop to accommodate small runs or get you by in a pinch until your desired size collet arrives.