Collet-ready Rotary Tables

June 01, 2011

If you've been using fixtures to grip parts on your rotary device, you already know how much operator intervention is required for setting up, clamping and locating the part, and changing from one job to another. And let's not forget about the design time and machining involved to produce the fixture itself. All of this accumulated time lengthens the production time and increases the cost of the part. Are there any other alternatives? Yes, collet-ready spindle rotary tables and indexers, manufactured by Hardinge accept a wide variety of standard tooling to grip parts of various shapes and sizes so that you can output more parts per hour at a lower cost per part.

But part cost isn't the only advantage of using a collet-ready rotary unit. Part quality is a factor and it begins at the spindle. Parts machined closest to the spindle bearings provide the highest accuracy with less wear on the rotary device. A hardened collet, step chuck or expanding collet will seat directly in the Hardinge spindle with the machining process closest to the spindle. Minimal overhang from the spindle bearings assure that spindle accuracy is transferred directly to the part being machined. Fixtures that are not hardened will lose positioning accuracy over time. Fixtures add weight to the spindle and move the cutting location further away from the spindle bearings.

Hardinge collet-ready turning centers, build the same A2 spindles into their rotary tables and indexers for increased precision and the convenience of quick setup and changeover with no adapter required. Collet-ready spindles will accept collets, step chucks, Sure-Grip expanding collets, FlexC quick-change vulcanized collet systems, custom collets, manual chucks and Sure-Grip power chucks. This tooling can be shared with a CNC lathe that you may already have in your shop. Collets and chucks will provide automatic centering of the part whether it is round, hexagon or square and will use less storage space than custom-made fixtures. If you'd like to continue using some of your existing fixturing, a simple adapter may be used.

Refer to the capacity chart provided for all of the gripping opportunities provided by a Hardinge collet-ready spindle rotary device. You can eliminate and replace heavy fixturing with higher precision, less expensive workholding products. Your premachined part could be gripped on a threaded or tapered outside diameter; an internal diameter; a square; a hex or any custom shape; or over a shoulder. Rough or slippery stock, thin wall and out-of-round parts, short grips, recessed grips and off-center parts are no problem. Castings, moldings, stampings and machined parts are held rigidly and accurately, while tubing can be held without crushing or distorting.

Collets will seat directly in the spindle for maximum gripping power and rigidity, providing the most accurate positioning available. Step chucks are simply oversized collets with a stepped-out face to grip larger part sizes using a closer. Step chucks provide extra grip force for short grip parts because the collet is closed against an opposing taper with 360-degree contact. Step chucks can have more than one gripping diameter for end-to-end machining or multiple use. Hardinge Sure-Grip Expanding Collets are used to grip the internal diameter of parts ranging from 18 inch up to 4 inches. Hardinge quick-change FlexC Collet Systems have an accuracy of within .0004" (.01mm). FlexC collets (42 and 65mm) are ideal for job shops that frequently change setups throughout the day because the collet heads change out in seconds. S-master style FlexC collets are available in 65 millimeter for shops that predominantly use S-pads with their other machines. Four-Jaw manual chucks will grip round, hex and square parts.

The Hardinge Sure-Grip 3-Jaw Power Chuck mounts directly on the rotary spindle to grip larger diameters and offers the best grip strength on the market. 3-Jaw chucks will grip round and hex shapes. Hardinge slotted face plates are precision ground for accurate locating of odd-shaped parts with guaranteed perpendicularity to the centerline of the spindle.

Related Glossary Terms

  • centering

    centering

    1. Process of locating the center of a workpiece to be mounted on centers. 2. Process of mounting the workpiece concentric to the machine spindle. See centers.

  • centers

    centers

    Cone-shaped pins that support a workpiece by one or two ends during machining. The centers fit into holes drilled in the workpiece ends. Centers that turn with the workpiece are called “live” centers; those that do not are called “dead” centers.

  • chuck

    chuck

    Workholding device that affixes to a mill, lathe or drill-press spindle. It holds a tool or workpiece by one end, allowing it to be rotated. May also be fitted to the machine table to hold a workpiece. Two or more adjustable jaws actually hold the tool or part. May be actuated manually, pneumatically, hydraulically or electrically. See collet.

  • collet

    collet

    Flexible-sided device that secures a tool or workpiece. Similar in function to a chuck, but can accommodate only a narrow size range. Typically provides greater gripping force and precision than a chuck. See chuck.

  • computer numerical control ( CNC)

    computer numerical control ( CNC)

    Microprocessor-based controller dedicated to a machine tool that permits the creation or modification of parts. Programmed numerical control activates the machine’s servos and spindle drives and controls the various machining operations. See DNC, direct numerical control; NC, numerical control.

  • fixture

    fixture

    Device, often made in-house, that holds a specific workpiece. See jig; modular fixturing.

  • lathe

    lathe

    Turning machine capable of sawing, milling, grinding, gear-cutting, drilling, reaming, boring, threading, facing, chamfering, grooving, knurling, spinning, parting, necking, taper-cutting, and cam- and eccentric-cutting, as well as step- and straight-turning. Comes in a variety of forms, ranging from manual to semiautomatic to fully automatic, with major types being engine lathes, turning and contouring lathes, turret lathes and numerical-control lathes. The engine lathe consists of a headstock and spindle, tailstock, bed, carriage (complete with apron) and cross slides. Features include gear- (speed) and feed-selector levers, toolpost, compound rest, lead screw and reversing lead screw, threading dial and rapid-traverse lever. Special lathe types include through-the-spindle, camshaft and crankshaft, brake drum and rotor, spinning and gun-barrel machines. Toolroom and bench lathes are used for precision work; the former for tool-and-die work and similar tasks, the latter for small workpieces (instruments, watches), normally without a power feed. Models are typically designated according to their “swing,” or the largest-diameter workpiece that can be rotated; bed length, or the distance between centers; and horsepower generated. See turning machine.

  • turning

    turning

    Workpiece is held in a chuck, mounted on a face plate or secured between centers and rotated while a cutting tool, normally a single-point tool, is fed into it along its periphery or across its end or face. Takes the form of straight turning (cutting along the periphery of the workpiece); taper turning (creating a taper); step turning (turning different-size diameters on the same work); chamfering (beveling an edge or shoulder); facing (cutting on an end); turning threads (usually external but can be internal); roughing (high-volume metal removal); and finishing (final light cuts). Performed on lathes, turning centers, chucking machines, automatic screw machines and similar machines.