|Colin Heseltine||17/05/2020 21:47:50|
|409 forum posts|
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.
|David George 1||17/05/2020 22:00:53|
1221 forum posts
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.
|Colin Heseltine||17/05/2020 22:03:59|
|409 forum posts|
That's a very good point I had not thought about.
|Andrew Johnston||17/05/2020 22:19:46|
5499 forum posts
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.
|1485 forum posts|
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.
|Clive Foster||17/05/2020 22:39:13|
|2204 forum posts|
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.
|Michael Gilligan||17/05/2020 23:29:44|
15707 forum posts
For small jobs, I use a Burnerd 4” 4-jaw on the BCA
... it works for me.
|Paul Lousick||17/05/2020 23:40:01|
|1408 forum posts|
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)
18104 forum posts
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.
|Colin Heseltine||18/05/2020 12:04:43|
|409 forum posts|
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.
|Clive Foster||18/05/2020 13:35:02|
|2204 forum posts|
+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.
|Michael Gilligan||18/05/2020 15:12:13|
15707 forum posts
Yes, of course it’s easier ... provided that you don’t want the flexibility of workpiece location that is offered by a four-jaw.
|Michael Cox 1||18/05/2020 16:09:37|
|531 forum posts|
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.
|Howard Lewis||18/05/2020 16:16:06|
|3267 forum posts|
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.
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