Can I use a rotary table for indexing?

For the most part, it appears as though rotary tables and dividing heads are separate tools. However, I'm wondering if I can use a rotary table for indexing. In other words, are all or some rotary tables convertible to an indexing head? Can I install a chuck and indexing plates? Is this normal, or is it the exception? I'd rather spend more money on a high quality rotary table that I can use for indexing than to have to buy two separate tools of lesser quality, if possible.

Thanks,
Jay

Yes, some rotary tables had indexing plates as an option:
Troyke
Pratt & Whitney's vertical shaper
Deckel
"Index" brand.

Browse ebay listings and you might see more examples, such as:
Moore Rotary Table Index Plates Parts 28139 | eBay

Some rotary tables have a tapered socket at the center of the table, to allow accurate centering, though I would expect any chuck might "walk out" if side forces were applied.

Phase II still sells an accessory kit which converts their rotary table to do indexing.

It is a very useful option to have. I have a Bison rotary table which came with an ordinary handle and a set of dividing plates, which can be used instead of it. Quite a nice rotary table. In addition it can do rapid indexing at 15 degrees independently of the dividing plates in the same way that some dividing heads do. If you have the option of getting this capability I would go for it.

Thanks for the replies, fellas. You confirmed what I suspected. I think I'll seek out a rotary table that can be retrofitted to serve as a dividing head as well, as it seems like you get more bang for the buck that way.

Jay

Yuasa makes a combination indexer/rotary table they call the "super accu-dex"

I learned about it after I spent all my money on rotary tables, super spacers, and dividing heads.


Chuck
Burbank, CA

Chuck Evans said:

Yuasa makes a combination indexer/rotary table they call the "super accu-dex"

I learned about it after I spent all my money on rotary tables, super spacers, and dividing heads.

Click to expand...

yeah, but you're far better off....dual purpose machines are usually a big compromise in functionality. A large diameter RT used horizontally puts a lot of table in the way, doesn't tilt to any angle and doesn't have a convenient chuck mount whereas a small dia RT is just well, lousy.

thermite said:

More bang for the buck yet if one has both and rigs to use a set of plates on either.

DH often have a different turns ratio to rotabs, and not an even multiple.

EX: Ellis DH, 40:1 Yamato Koki / News /Yuasa Rotab 90:1

With a 'tables' for the hole-count and turns for both, one can use a given plate to fill-in the odd gap by deriving different divisions on each.

Get whichever has the most immediate use first, plan that it won't be your last-ever acquisition. One DH may long serve you. One size-only of rotab, seldom as lucky.

Bill

Click to expand...

An example of what Bill is describing: I first bought a Japanese copy of a B&S 0 40:1 dividing head. A little later, I bought an Enco Taiwan 8" 90:1 rotary table with vertical attachment, tailstock and dividing plates. I designed a device that required sets of gears, one of which I could not cut with the B&S plates. But I was able to use the Enco tool to drill a new plate for the B&S that let me cut the gear with the B&S. A rotary table is ideal for drilling plates for dividing heads. The Enco rotary table is too big in the vertical position to conveniently cut small gears, which is why I want both tools.

Look at DIVHEAD.ZIP here for a useful program for dividing heads: http://www.myvirtualnetwork.com/mklotz/#shop

Larry

git both or hang it up.
just kidding,however,I hate fiddle-farting,,even though as a Machinist it is kind of like a given middle name "hey fiddle-fart".
IMO,treat it as 2 different tools and come out ahead.
For that matter I got an 5c indexer,a dividing head,A 8 inch Super Spacer and 2 different sizes of Hor/Vert. RT

It sort of depends on what you are trying to index. I would not attempt to make a gear, indexed on a rotab, even with dividing plates. For a milled hex a super spacer is much faster and good enough for a wrench or socket. For a bolt circle I'd use the DRO functionality (if present, or manually calculate X-Y coordinates) which is no indexing at all and saves dismounting and re-indicating the vise. All are useful additions to (or fixtures in) one's shop and all have their place as a timesaver, as mentioned above.

What size rotary table would you ne interested in finding, and would it have to be a flat vertical axis of rotation or a dual-orientation one?

I have a Walter HU-80 dividing head that has a built-in 24 position index plate, and I can rotate the head from horizontal (using tailstock) up to 90º straight up. That gets a bit tall, though it's still a relatively low profile head compared to other makes. I have a 150mm 3-jaw chuck, a collet chuck, or center with dog driver. Walter also made some incredibly smooth, accurate rotary tables which had true dividing head gearing and plates, and many of those can disengage the worm and use a non-interchangeable quick index function that's built in below the table. Those tools are most definitely high end tools, and worth every penny if that's what you need.

Walter Dividing Indexing Head with 9 Plates | eBay
Walter Type RTS 500 TG Rotary Table Indexing Tilting | eBay
Walter RTS 800 31" Power Tilting Rotary Table Pristine | eBay

And I would not hesitate to cut a gear with a rotary table of that caliber!

They both use worms to rotate in precise increments. The difference is in the details as each is set up to be better for different tasks. But, yes you can divide on a RT. Many, dare I say all of them, can be fitted with dividing plates. Or you can just find the angular positions and go to each of them in turn. That may be more prone to error than using plates and an arm with a pin, but it does work. I have done it.

Is the size of a RT really in the way. Well, perhaps, but I have never been unable to work with it and I have a 10", which is BIG. And heavy! I dropped it once. Big ding in the floor, no noticeable damage to the RT. It is BIG and MASSIVE. And probably a lot more accurate than most dividing heads.

And you can probably do small RT jobs with a dividing head.

PS: If your RT did not come with dividing plates and none are available, you can make a set using the table itself. I previously posted this elsewhere, so I am quoting myself;

You CAN make a set of circles on your own, using ONLY the dividing head or rotary table you already have. They WILL be just as accurate as your worm gear is, with a small bit of random error due to the uncertainties of the machining process. I have described this process several times and you can search this site (Activity Stream - The Home Shop Machinist & Machinist's Workshop Magazine's BBS) for these lengthy explanations, but here are the short strokes:

As someone stated above, a second generation plate made with YOUR existing head will be 30 (or 40 or 90) times more accurate than the first generation plate used to make it. The worm gear acts as a "precision amplifier". So if you have a one degree error in a first generation plate, the second generation plate will have only a 2 minute (1/30 of one degree) error. And when you use that second generation plate, the error on your work will be only 1/30 of that or 4 seconds of arc. I will guarantee you that your worm is not that accurate and no further precision is needed.

So to generate a new plate with any number of holes:

1. Make a first generation plate using any layout technique that you want. Literally ANY technique: the accuracy DOES NOT MATTER. If you can get the holes within 2 or 3 degrees of the correct positions that is 100% good enough. You do not even have to drill these holes, simple pencil marks on a paper disk and a pointer on the shaft will work. And by "will work" I mean that it will provide the accuracy I have stated above on a third generation plate.

2. Use that first generation plate to drill a second generation plate.

That's it, you are done and your work with this second generation plate will, WHEN USED ON YOUR HEAD, will be the third generation and will be at the accuracy that I stated above (4 seconds of arc or better plus the error in your worm). Thus you have made one "paper plate", the first generation and a second generation metal one.

One small note. The second generation plate made above is not at the high level of accuracy I claimed above BUT it will provide that level of accuracy when used on your head. If you want a highly accurate plate for direct use instead of one to be used on your head, then you would need to make a third generation plate to get that accuracy.

This is not magic, it is simple math.

MATH ROCKS!

I have a 10"hv rotab with plates and sector arms.When I get back from vacation I have to make 3 10dp.63 tooth 6.5"od gears.I might have to use it and while I have never cut any gears with it I don't anticipate any problems.I have a universal head but don't know if I have the necessary gears to differential index index it,so the rotab might have to work.Don't see any reason why it would be any less accurate than my dividing heads.

Don't underestimate how large and heavy a rotary table can be. I have a 12" horiz/vert rotary table without indexing capability. It weighs 200 lbs. I need a hydraulic lift cart to move it around the shop. I also have a nice L-W dividing head. It does everything I need for indexing, and it is much more portable. It also tilts on one axis, which the rotary table can't do. I agree with some other posts that it's hard to find a one-tool-does-it-all solution. It might do it all, but it won't do anything well.

Check your local CL for rotary tables, when I was looking, they were plentiful. I bought my dividing head on Ebay for what I think was a good price.

-Justin

Weight is an important factor in how much you will use a rotab or a dividing head. My rotary table is 10"; I could possibly lift it if I tried, but it would be stupid to do so. Same with my dividing head but more so. A rotary table gets more useful as it gets bigger and in my experience features such as dividing plates are more common on larger ones. But if you don't work out how to move and fit them on your mill quickly, you will be less inclined to use them. A die cart or something similar is good; I use a folding engine hoist which is not as usable, but does the job. If you use a hoist for this, you can speed things up a lot by making a small trollies with casters on which to store the table or dividing head. Then you can just push them into the best position on the floor to pick them up with the hoist. Same thing when putting them away.

Yep works just fine. I was making a fine feed handle for my Lagun and didn't want to go grab my DH so just used the dividing plates on the rotary table. And they can be stood vertical. Of course they have all the drawbacks noted above with stability and not tilting and such.

For me in this case it was just a matter of not wanting to lift a 170lb DH up onto the table and have to remove and reset up the rotab later. But really you should have both.

Basic Bridgeport rotab with the dividing plates installed.


Then switching the plates out for the handle when things are set up but just need a smooth turn to actually mill. In these type of situations it can be convenient.


Would not give up the accuracy and adaptability of a universal DH those. Especially considering how cheap they can be had now...ignoring the eBay idiots of course.