Rotary Table Chucks

Having just finished making the Stephen Ward Division Controller and fitted it to 6" Homge Rotary Table. I now need to source a suitable 3 jaw chuck. I am looking at a range of chucks (in the hopefully better quality range); Vertex 125mm, TOS 125mm, Pratt Burnerd 125mm . There are options with most of these for front or rear mounting.

I obviously need to make a subplate/backplate to mount to the RT (3 slotted) but my question is am I better of with front mount chuck or rear mount chuck. My thoughts at the moment are towards front mount.

What are your thoughts/rcommendations.

Colin

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

David,

That's a very good point I had not thought about.

Colin

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

Front mounting is useful as you can turn a part on the lathe and then transfer the chuck to the rotary table without removing the part and keep the part concentric, you just need a turned stub to fit the chuck bore and the hole in the table, with 3 slots in the table you should be able to fix direct to Tee nuts.

Emgee

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

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For small jobs, I use a Burnerd 4” 4-jaw on the BCA

... it works for me.

MichaelG.

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.

I think 3 jaw is a lot easier if using the R/T vertically as quick and easy to set up particularly if you are just going to be using the division control for indexing, I find odd shapes I'm more likely to be milling with it horizontal in which case clamps work for me and a easier as the work is on a flat surface rather than wanting to drop off a vertical one.

I have two 3-jaw chuck on backplates that have never been off them since bought so screws would not make a lot of difference as only used once.

MT socket is good for small diameter work as finger collets will fit or you can stick a MT equiped ER collet holed in two, again when used vertically these give more clearance for the spindle or tool holding collet than a chuck so you can get away with less stick out of work and/or tool.

Remember that if holding long work a solid locating spigot or separate peg can block the hole.

I do have a MT2 mandrel with a Myford nose thread on it. Problem is it sits way way too far above the surface of the RT.

Currently waiting for a delivery of a small backplate for rotary table which has Myford nose thread on it. Can then use one of my small chucks for the present.

Colin

+1 to Jasons comment about a 3 jaw being easier when using the rotary table in a vertical mode.

I have a 5C spindexer and consider the 3 jaw chuck on a 5C spigot an essential accessory. Despite having full sets of both imperial and metric 5C collets. It sees lots of use.

I also have 3 horizontal-vertical rotary tables, 8", 10" and 12". I think each has been used once in vertical mode! Overall less than one use per decade. Used the 12" last time. Hefty brute. Quite scary standing it up on end and getting all aligned with the Bridgeport table.

Clive

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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.

The most useful chuck I use on my rotary table is an ER32 collet chuck on an MT2 morse taper. This also fits into my lathe using an MT2 to MT3 adaptor. THis is especially useful for gear cutting because you can turn a part to size on the lathe and transfer to the rotary table with no loss of concentricity.

Mike

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've enjoyed reading this thread. every post has had something of interest.

Just bought the Axminster 110mm table and initial impressions are certainly good.

A few glitches but nothing that couldn't be sorted quickly.

Have spent the day making a sub table and mounting a 4 jaw chuck on it.

I would like a 3 jaw as well for the same sub table.

So a question. I notice that chronos are doing a soba 100mm chuck with front mounting for a penny under £70.

The price is right but what's the quality like?

Has anyone any experience of this chuck or soba chucks generally?

Geoff

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.

Hi Andrew,

Thanks for your reply.

Just had another look at the chronos "soba" chuck, listed as soba but in the details it is classed as unbranded which would seem to confirm what you said.

Had a look at the Arc chucks. I notice they have an 80mm 4 jaw s.c. which is on offer. It also has the front mounting which is what I need. Looks good value and is probably good enough for my needs. Made by ZITHER?

I have bought a lot of stuff from Arc, never been disappointed yet.

ZITHER chucks anyone, opinions?

Geoff

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 have small 3 and 4 jaw chucks that can be fitted to my Vertex HV6, using a 2MT/Myford arbor.

Don't think that i have ever used the 3 Jaw. The 4 Jaw is used, often in the lathe, fto get things clocked up for turning, before transferring to the HV6 (often for gear cutting )

FWIW get a 4 jaw and /or make a suitable arbor. In that way you can be sure that work will be as concentric, or eccentric, as you require.

A 3 Jaw will be most unlikely to give you concentricity as good as you can get with a 4 Jaw and a DTI.

Howard

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!