I fitted my rotary table with front mounting as it was easier to mount the plate clock the location true then screw the chuck to the back plate to run true.

David

Having acquired a manual vertical/horizontal rotary table many years ago I rushed out and bought a 3-jaw chuck for it. But I've never fitted it and in retrospect have never missed it. My rotary table has a parallel centre hole, so it's easy to make mandrels to align parts. I've never understood the 'advantage' of having the centre hole be a Morse taper.

To be fair my dividing head has an indexing plate behind the chuck so it's easier to use that, as a sort of spin indexer, for machining squares and hexagons.

The rotary table for the CNC mill has a commercial 5C collet chuck on a home made backplate, as most parts needing a 4-axis CNC mill can be mounted on arbors.

Andrew

A 4 jaw chuck may well be more useful than a 3 jaw as assymmetric components can be held. Generally no great need for accurate concentricity between table and chuck if using a 4 jaw as you have to clock the job central anyway.

If three jaw accuracy is sufficient then tightening the chuck onto a post dropped into the MT or parallel bore in the centre of the rotary table to align it before clamping down will generally be satisfactory.

Before investing serious money in a chuck for the rotary table have a good think about the type of jobs you intend to be doing. There may well be more cost effective methods of dealing with things. I've frequently thought about sorting a proper method to mount one of my "spare" chucks onto a rotary table but never found sufficiently common needs that justified a proper job. On the three or four times in the last 20 years that I recall so mounting a chuck I simply used standard clamps hold it in place. Probably aligned by the centre post method.

Back in the day a mount the same as the lathe spindle nose fitting set into the rotary table central hole was considered handy for swopping work between lathe an rotary table without loss of concentricity. Stiil I think one of the most valid needs, but I'd need DI-4 and D1-5 camlock plates!

Possibly my most used mounting system after the clamp set is a simple "improved wood" plate drilled to register with the centre post alignment device bolted down with a couple of Tee nuts with the job secured by chipboard screws. Assuming successive examples knocked out for specific jobs and disposed of count as one device. I use whatever is to hand. Ex kitchen cabinet usually. Sides or worktop. Skimmed flat if need be for a precision job. Generally "as is" is close enough.

Clive

I find that a 4-jaw chuck is more useful as it can hold odd shaped parts. Getting round parts on centre does not take very long with a dial indicator.

I have an RT with 4 slots and the 4-jaw chuck has 4 thru holes and can be bolted to the RT without a backing plate and a spigot keeps it central. Not having a backing plate allows you to fit a larger chuck (same diameter as the RT)

Paul.

.

Yes, of course it’s easier … provided that you don’t want the flexibility of workpiece location that is offered by a four-jaw.

MichaelG.

What Mike Cox does is exactly what I do for gear cutting.

The set up is a bit cumbersome,a Myford fitting chuck on a 2MT Myford arbor, with a 3MT sleeve for the lathe, (which is removed before taking the work to the Rotary Table ).

The workpiece, or the arbor on which it is mounted, has a centre drilling, so that it can be supported by the Tailstock for the Rotary Table.

In this way, the work is better supported to withstand the forces involved in gear cutting.

Howard

I have not been too impressed by Soba chucks. Soba do not make chucks,I am told, but buy them in. So there could be good ones around depending on who made them.

If you want a cheaper chuck, then Sanou seem to be making excellent chucks. I have just got one from Arc (although it is marked Arc, I am sure it is a Sanou, badge engineered version). It is also a lot less than the Soba 100 from Chronos.

Other people may well disagree, I am basing my opinion on two Soba chucks and what I take to be an Arc/Sanou chuck. So all is based on a VERY small sample!

Andrew.

If you ever need to do some division on a part that has to be concentric, such as a gear, then a 3 jaw is unlikely to be the right choice unless it's a very expensive one and you mount it very carefully. If you've mastered centreing in the 4-J on the lathe it's easy to transfer the technique to the RT, though a bit slower unless you can disengage the worm.

I have a Vertex 6" HV table and I've drilled & tapped it to take my 4 jaw.  In all the time I've had the RT it has been used precisely once, though I can see I'll be using it again soon for a job that won't fit on the CNC mill.

Edited By John Haine on 04/12/2020 09:36:31

I was standing next to someone at an exhibition at a trade stand, who was looking at a tiny tilting rotary table with 3 slots and a tiny 3 jaw chuck, both at the lower end of the price range. He was obviously unsure whether the chuck would fit – I asked him what he would do if the chuck wasn't central when it was mounted? After a few moments of thought he changed his mind!

Mine has a straight bore,so I made a fitting with a threaded nose for my myford.I found that the chuck was not supported enough as it did not sit on the table,I overcame this with a circular ring just a thou, or two above the end of the register of the adaptor and this made for a ridgid set up.I put a centre dot in the adaptor whilst being machined and this helps when centreing the RT.

Frank

Earlier this month, in this thread, I asked the forum for opinions on Zither lathe chucks.

I had no specific replies but nevertheless decided to take the plunge and buy one from Arc.

I chose the 80mm, 4jaw, self centering chuck which Arc currently have on offer at £73.

Have to say I'm pleased with the purchase.

A few grumbles when it came out of the box, sharp corners which need minor fettling and careless number punching around the jaws slots but otherwise initial impressions were good.

I turned the register on the backplate to a precise fit in the chuck recess, drilled and tapped for the front mounting bolts, assembled the two and screwed it back onto the spindle nose.

With a short length of 5/8" silver held in the chuck I was ready for the real test of this chuck. For me to be happy, with the lathe running the bar would have to appear, APPEAR, to be running true. Well it most certainly did visually run true.

I then clocked it with a D.T.I. and it ran out by less than 1/2 thou which for a £70 chuck I would say is very good. Tested it with other diameters with the same result.

Overall at least an 8/10 chuck especially at the price and a big thumbs up for arc again, I have never been disappointed with any purchase from them.

geoff