For both accuracy and efficiency the philosophy of not letting go once you have located a part is the ideal workholding choice. Nowhere is this better demonstrated than by the indexing chuck.
It is not a new concept, but indexing chucks offer significant advantages for difficult to hold components that would require multiple or staged fixing that could introduce errors. Component accuracy is derived from the indexing accuracy of the chuck as all the machining is effectively related to the first datum setting.
Over the years the range of components making use of the indexing chuck has become increasingly diverse, as designers and production engineers become aware of the benefits and flats or dimples for location and clamping are being included in the cast or forged raw component material. These features simplify location and can even reduce the size of the chuck required in many instances.
Manually indexed the chucks, which can be manually or power clamped, also support the drive towards lean manufacturing as the ability to fixture a part once helps improve profit margins on shorter batch runs. Even though these chucks provide a complete solution for a specific application they do so without compromising the flexibility of the lathe. The quick change philosophy we promote has also been adopted here, and a fully manual chuck can be removed from a typical turning centre in under 10 minutes. The cost of the investment is also not prohibitive with manual indexing chucks starting at £5,000. So there is no penalty for investing and installing a bespoke solution.
A wide range of 2-jaw self-centring indexing chucks in diameters from 125 mm up to 500 mm is available. Specifically-designed for holding valve bodies and similar fittings, the chucks feature interchangeable indexing plates. Usual divisions are four 90o movements with an indexing accuracy of +/- 2 seconds of arc, but divisions of any incremental angle can be specified.
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