'Zither' (Indian) 3-jaw self-centring chuck - excellent!

I have a small ancient (1920s?) German Lorch Schmidt watchmakers' lathe - a basic mini-lathe with a 60mm 3 jaw self-centring chuck. Despite its limitations, the lathe does all that I want from it, but the run-out on the chuck has progressively got worse over the five years or so that I've had the lathe, and reached the stage where it was unacceptable. (25 thou in fact). Some of the items I turn on the lathe are from 50mm diam plastic bar and don't call for great accuracy, so 25 thou is tolerable. However, I make other things from 6mm brass rod, drilled out to 2.5mm so 25 thou is out of the question.

I've tried all the suggestions I've found on internet to reduce or cure the run-out, none of which have brought about an improvement, including dismantling it and cleaning the scroll etc in an ultrasonic bath prior to re-assembly . There is no run-out on the backplate or body of the chuck, but there is on stock of any size inserted into the chuck. I concluded that quite simply, the chuck has gone to the 'workshop in the sky' and must be replaced.

I know that self-centring scroll chucks aren't noted for their accuracy, and am prepared to sacrifice a little accuracy for the convenience of a self-centring chuck. I searched around and thee aren't too many 60mm chucks on the market - the one that caught my eye was a 'Zither' Indian made chuck from Arc Euro Trade. (Their Part Ref No: 040-040-00900). I was as sceptical about buying an Indian made chuck as I would be about a Chinese one so I made the trip down from Hull to Leicester to see a chuck for myself before I took the plunge. I was impressed by the spec: within .08mm (3 thou) on a test bar, and .03mm (1 thou) on the face and periphery of a test ring held internally and externally. The chuck and its two sets of jaws were all stamped with the same serial number and the test certificate which accompanied the chuck indicated that it was within tolerance.

I had to make a back-plate for the new chuck as the thread on the spindle of my lathe is the rather odd size of 19mm x 1mm pitch. I got a chum with screw-cutting facilities to cut me the thread in the back-plate, which I then mounted onto my lathe to carefully turn it down to register with the new chuck, and to drill and tap the three M5 holes in the back-plate to secure the chuck to it.

I have to say that I'm delighted with the chuck, which shows no run-out at all on a DTI. I've since looked up Zither on internet to find out more about the firm, (who I'd never heard of), and note that they've been in business since 1948 and are an ISO 90001 company. Arc Euro Trade stock a range of Zither chucks as well as Chinese ones - the Zither ones being a little more expensive, but still excellent value for money from my perspective.

Based on my experience I'd have no hesitation in recommending this make to others, and for the avoidance of doubt, I should add that I've no connection with Arc Euro Trade (or any other firm come to that), other than as a satisfied customer. (I've found Ian there very helpful, knowledgeable, and courteous).

I hope this feedback might be of help to others in a similar predicament with a dodgy self-centring(not!) chuck.

Quite simply, if you've tried the cowboys, why not try the Indians?!!!

I must admit, after talking to Ketan I decided to take his advice and splashed out the extra for a 4" Zither SC chuck. If I posted the DTI results I've got, no-one would believe me except you. One caveat - the chuck MUST be clean to get the really good results.

Neil

A chuck that size might answer my quest for a 3 jaw for my Super Adept, the lack of which reduces the amount of use the little lathe gets. Must see if any where around here has Zither chucks. Ian S C

Hi Ian,

Sorry they are not sold in New Zealand or Australia. At present, to the best of my knowledge, outside India, ARC is the only company who stock and sell it. Inside India, the Indian dealers also have to wait until ARC places an order, to piggy back, because we are the only company who places an order large enough for them to consider production of this size. Generally, demand within India for this size is low.

Originally, this chuck was designed and made for ARC by Zither, after they reviewed several samples which we sent them from the U.K..

Now days, there are other Indian manufacturers for this size, and lower diameters too, but ARC is happy only to work with and issue guarantees for Zither made chucks.

A bit of history: Originally, the founder of Zither - back in 1948 appointed dealers throughout India. Third generation of Zither are entering the trade, joined by third generation of the dealers originally appointed in 1948!. Believe me, such level of loyalty on both sides is difficult to find in India.

In the past, I have worked with many Indian dealers and manufacturers in different industries. The respect, commitment - word of bond which Zither commands is difficult for me to find or consider for anyone else, regardless of how big the company may be.

Ketan at ARC.