Product category:
Chucks and collets for rotational work
News Release from: Leader Chuck Systems | Subject: Zweifel instrument chucks
Edited by the Manufacturingtalk Editorial
Team on 27 June 2003
Instrument chucks hold delicate parts
for turning
Machining delicate jewellery items from precious metals demands special care, and in terms of workholding it is essential the high-value workpieces are held both safely and securely.
Machining delicate jewellery items from precious metals demands special care, and in terms of workholding it is essential the high-value workpieces are held both safely and securely, as well as being located accurately and repeatedly to avoid marking or damage Leading high-class jewellery manufacturer Nicholas Philippe has found the perfect solution to this: Zweifel instrument chucks supplied by award-winning workholding specialist Leader Chuck Systems
This article was originally published on Manufacturingtalk on 23 Jun 2008 at 8.00am (UK)
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Capable of fast changeovers, a collet chuck has a runout accuracy of only five microns and is a replacement for other styles of collet chucks in bar-fed turning applications.
In addition to satisfying his particular workholding needs, the precision miniature six-jaw chucks have also saved him time and money.
Prior to buying the chucks, Nicholas Philippe used to make all his own collet-style workholding equipment for use on two precision watchmaking lathes and a milling machine.
"These systems worked well," he explains, "but they were relatively expensive and time consuming to produce, and because my work varies so much I might only use them once.
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A turning centre fitted with precision collet chucks on its main- and sub-spindles is central to a subcontractor's successful policy of machining small batches of precise, complex parts.
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Capable of fast changeovers, a collet chuck design has a runout accuracy of five microns and is as an economical replacement for multi-bore and other styles of collet chucks in bar-fed applications.
"What I needed was a versatile and highly accurate chuck which would consistently and reliably operate to within +/-0.001mm.
But it proved difficult to source such a precision system which was also reasonably priced." However, he did find exactly what he wanted from Leader Chuck Systems.
"The Zweifel chucks were the only ones that came up to scratch in terms of quality, accuracy, repeatability and value for money," he says "and I bought three - two 50mm capacity units and one 80mm chuck along with several sets of soft jaws for both internal and external gripping." These are in regular use on both a Schaublin two-axis lathe and a Sixis mill installed at the company's workshops in Hatton Garden, London.
Zweifel manual instrument chucks are available in a range of diameters from 50mm to 150mm with up to eight jaws.
They feature soft, false multi-jaws and are therefore ideal for gripping thin-walled components.
Nicholas Philippe specialises in individually-made diamond dress watches (particularly customising such brands as Rolex, Cartier and Bulgari), fine engineering in precious metals, diamond mounting, master patternmaking and fine jewellery restoration as well as engagement and wedding rings.
He also makes fine jewellery items such as pendants, cuff links and shirt buttons.
Having previously worked for the legendary Paul Kutchinsky, he is rapidly establishing a reputation for personalising diamond inset dress watches.
This involves the precision manufacture of specialised bezels, dials, bodies and bracelets in 18ct yellow and white gold and platinum, and often only 1.5mm thick.
Most contracts are one-offs and he produces 30 to 40 personalised watches each year.
Bearing in mind the cost of such specialised items - in one instance, a standard Rolex dress watch trebled in price after being customised - and the high added value content which is dependant on the size and grade of the gem stones used, extreme care and attention to detail is obviously essential throughout the manufacturing process.
Typical machining operations on dress watches include profile turning, drilling, boring, recessing, tapping, some decorative-type work and parting-off.
Cast gold bar up to a maximum of around 55mm square can be turned on the Schaublin lathe and holes from 1mm to 4mm diameter are machined to accommodate the round diamonds.
Pockets for gems of other shapes (notably square and hexagonal) are produced on the mill.
Polycrystalline diamond tooling is used for all turning operations and the average cycle time for machining a special bezel, for example, is 5 to 10 hours.
"The chucks' main benefit," continues Nicholas Philippe, "is that I no longer have to produce special, individual collets for each new job.
This saves me both time and money, and because I can get on with a new project straight away I am able to reduce my lead times.
As well as being highly accurate and repeatable, the chucks are extremely versatile and the large knurled adjusting ring means that I can actually feel the gripping forced being applied." Other items of jewellery being machined include 10mm OD cast cuff links (in both gold and platinum) and a series of special 18 ct gold shirt buttons.
As well as finish turning the cuff links, the master pattern for these cast items was also produced on the two-axis lathe using a Zweifel chuck.
Among forthcoming projects is the creation (by turning) of a master pattern for a series of cast 16 mm diameter doughnut-style gold pendants.
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