mounting 3 jaw chuck rotary table free sample

I"m a wanna-be machinist newbie. I have a small mill (no lathe). I obtained this small 6" rotary table (a Griz product). I would like to get a small 3-jaw chuck mounted to it, but have NO CLUE as to how to choose a chuck that will be compatible with this RoTab. Am I looking for a 6" chuck? Or 4"? I can"t go too "tall" or I waste all my Z axis. I don"t even know how the chuck would mount to the RoTab. The hole in the center is a MT#2, would a chuck use the MT? Or attached how?

Can someone guide me to some options regarding how to get a chuck on here, where to find the components needed? I am not looking for gold-plated accuracy. (It"s just an inexpensive $900 ChiCom mill with an inexpensive $250 ChiCom RoTab. Not proud of it, but I"m lucky to have it, and it works good enough.) In fact I"d love to buy a chuck used if possible and save some coin. Ideas?

More info on my intended useage of chuck-on-rotab, if you are interested: This RoTab will mount horizontal or vertical. With the RoTab in the vertical position, with its associated tailstock, I believe you can "fake" some lathe operations on a mill. I need to do some small lathe operations with it, which will entail bringing down an endmill to the work and then slowly turning the RoTab. So sort of reverse of a lathe, in this setup the bit is powered and the work is being turned slowly by hand. Yeah, I wish had a lathe but in this obanomy, you make do with what you got.

Alternately, I think I can do some vertical lathing without the RoTab. If the stock is small enough to go into the mill"s chuck (5/8 max) and stout enough to hang free, some lathing can be done by clamping a lathe bit in the vise and running it up and down the work using the Z axis. For small work only.

I suppose you could also chuck a larger round piece in the rotab/chuck (with the rotab/chuck in the horizontal position, and the work sticking up vertically), and use an endmill to make bushings, and other short, squat round work, etc. by spinning the work in the rotab/chuck against the endmill.

I am thinking of mounting a 6 inch chuck. The table has 4 T-slots that do not go all the way to center. I do not as yet have the chuck, so suggestions as to what type, brand, size, back plate, etc will be appreciated. Also will modifications to a typical chuck be required to accomplish the attachment.

Comments for technique of centering up the chuck on the rotary table would also be appreciated. What I had in mind was to make up a mandrel that would fit the #3 Morse Taper center hole int the rotary table and extend through the chuck, so that I could close the chuck on the mandrel to align it before clamping the chuck to the table

If you use a three jaw on your rotab, it needs to be an adjust tru type so you can set your work up concentric to the rotation every time. Just like on a lathe, the three jaw is just ballpark center.

The other option is a four jaw. That"s what I"d do unless you plan on production or very repetitive work, where the adjust tru would remain centered for multiple chuckings on the same diameter.

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MikeC wrote:The other option is a four jaw. That"s what I"d do unless you plan on production or very repetitive work, where the adjust tru would remain centered for multiple chuckings on the same diameter.

This is my option. I have 4 jaws for (not always on) my 6" Hartford Indexer and my 12" Troyke. Easily mounted when needed, holds (mostly) arbitrarily shaped parts, and easily "dialed in" for whatever feature needs to be concentric.

Bill_Cook wrote:Another advantage to the 4 jaw is that it has 4 mounting holes like the table, and won"t likely need a back plate. It pays to keep setups close. BCPlease elaborate ? I am unaware of any holes in a chuck that would be useful for mounting it to a rotary table or why there is anything inherent that would result in a 4 jaw having exactly 4 holes Is this perhaps a particular characteristic of the brand or model of chuck you have?

Most all 4 jaws (those that do not have integral mounts) have 4 holes for attaching a back plate. These holes are generally located between 1/3 and 1/2 of the chuck radius from center, and between each of the 4 jaws. A quick search on ebay turns up this example which shows it quite clearly.

Oh, and this is not characteristic of any brand, but rather a characteristic of "universal" chucks intended for use with a back plate matching the intended spindle. I have 2x8" Pratt Burnerds, 1x8" HD Cushman, 1x6" Pratt Burnered, and 1x10" Buck; all with the same 4 bolt pattern in the face...

BadDog wrote:Most all 4 jaws (those that do not have integral mounts) have 4 holes for attaching a back plate.Thanks BadDog, my 4 jaw that came with my lathe has the integral mount so that is why I had not seen this feature. I can see how that would help, provided the bolt holes are large enough to provide adequate attachment via T-nuts in the slots. The ones on the e-bay chuck look a bit small for that use. Is that all that secures the chuck to a back plate? They seem a bit puny for a chunk of iron like that chuck plus what it is holding when doing turning on a lathe.

The bolts on on 10" Buck chuck are 7/16 SHCS (if I recall correctly). The main locating feature is the register, so the bolts are more than adequate.

Use a piece of aluminum plate that has been faced parallel by turning both faces at least two times. That way you relieve the internal stresses and end up with what is a reasonably flat and parallel. I"d suggest plate no thinner than 3/4", to allow for the SHCS"s that will be required to mount the plate to the rotab without having any projections.

Turn the OD (same diameter as the rotab) and a register that fits the inside of your chuck, and if you have what I prefer in a rotab, a straight bore instead of a Mores taper, bore a hole on center that will accommodate a locating spud so you can drop the plate on your rotab and have it very close to center. Drill and counterbore the back side of the adapter plate for the socket head mounting screws that will be used to mount the plate to the chuck, then on the opposite face, drill and counterbore four holes (don"t forget to allow clearance for the chuck body) that will allow the plate to be bolted to the rotab using the T slots, again, with SHCS"s. Done.

Make sure the locating spud is easily removed so you can insert long shafts when necessary, or if you must dial the chuck to center when holding specific sizes. By choosing this method, you can avoid an adjust tru chuck and still achieve the same results. The chuck becomes even more useable if you have soft jaw capabilities.

Soft jaw capability is the only thing that makes me consider mounting a 3 jaw on the rotab. I"ve wished for it a couple of times. But then I"m so cheap it actually HURTS to have to cut a soft jaw for a single job, though I do it. Once I get the new lathe tooling in order, I really need to break down and make a dozen or more sets so I"ll quit feeling like I need to save every ounce of metal I can (to avoid "using them up" and needing to make more).

Anyway, for a 3 jaw, I don"t use it often enough for "speed" or "per part simple convenience" to matter. In fact, no more than I use it, considering the up-front cost, I would probably never make up the time it took to mount the thing. My 4 jaws were all dirt cheap and easily mounted with 4 bolts and t-nuts. And with the 4 jaw I can just set it on, get it somewhere in the vicinity of close, bolt it down, then dial the relevant feature using the jaws. Not much longer to do that fooling with a 3 jaw AFTER it"s been mounted/adapted, but without the up-front cost in money or time.

For my 8” Phase II rotary table, the 6” chuck mounts to an 8” back plate giving a 1” lip all the way around to make it easy to bolt the chuck/plate assembly to the rotary table T-slots. There is also a round alignment disk (roughly 1.25”D that fits snugly in a hole in the center of the RT directly above the MT socket and a matching hole in the center of the mounting plate. Presumably the intent of this alignment disk is to allow you align the chuck to the plate and RT once, and subsequently all you need to do is re-bolt down plate to RT next time. However, in practice I tossed the alignment disk aside, as there is no avoiding using a DTI to align the chuck to the RT every time it is mounted since tightening the bolts to the RT impact the alignment at the nose of the chuck by quite a bit. When I got an indexer and a dividing head, I made sure they could accept 5C collets and had the same spindle nose as my lathe so I can move chucks and collets between the lathe, indexer or dividing head without any of the realignment hassles.

The reverse rotary table is perfect for using on the tilting angle table. The reverse mount allows access to the handwheel from the front of the machine (see photo below). If you used a standard rotary table in the previously described set-up, the handwheel would be mounted facing the backside of the X-axis.

NOTE: When the worm housing is reversed to the opposite side, a clockwise rotation of the handwheel or stepper motor will result in a counter-clockwise rotation of the rotary table.

The rotary tables can hold more weight when they are not under a continual load. Click on the Video tab above to see examples of different weights and uses for our rotary tables.

A rotary table is a precision work positioning device used in metalworking. It enables the operator to drill or cut work at exact intervals around a fixed (usually horizontal or vertical) axis. Some rotary tables allow the use of index plates for indexing operations, and some can also be fitted with dividing plates that enable regular work positioning at divisions for which indexing plates are not available. A rotary fixture used in this fashion is more appropriately called a dividing head (indexing head).

The table shown is a manually operated type. Powered tables under the control of CNC machines are now available, and provide a fourth axis to CNC milling machines. Rotary tables are made with a solid base, which has provision for clamping onto another table or fixture. The actual table is a precision-machined disc to which the work piece is clamped (T slots are generally provided for this purpose). This disc can rotate freely, for indexing, or under the control of a worm (handwheel), with the worm wheel portion being made part of the actual table. High precision tables are driven by backlash compensating duplex worms.

The ratio between worm and table is generally 40:1, 72:1 or 90:1 but may be any ratio that can be easily divided exactly into 360°. This is for ease of use when indexing plates are available. A graduated dial and, often, a vernier scale enable the operator to position the table, and thus the work affixed to it with great accuracy.

Rotary tables are most commonly mounted "flat", with the table rotating around a vertical axis, in the same plane as the cutter of a vertical milling machine. An alternate setup is to mount the rotary table on its end (or mount it "flat" on a 90° angle plate), so that it rotates about a horizontal axis. In this configuration a tailstock can also be used, thus holding the workpiece "between centers."

With the table mounted on a secondary table, the workpiece is accurately centered on the rotary table"s axis, which in turn is centered on the cutting tool"s axis. All three axes are thus coaxial. From this point, the secondary table can be offset in either the X or Y direction to set the cutter the desired distance from the workpiece"s center. This allows concentric machining operations on the workpiece. Placing the workpiece eccentrically a set distance from the center permits more complex curves to be cut. As with other setups on a vertical mill, the milling operation can be either drilling a series of concentric, and possibly equidistant holes, or face or end milling either circular or semicircular shapes and contours.

To create large-diameter holes, via milling in a circular toolpath, on small milling machines that don"t have the power to drive large twist drills (>0.500"/>13 mm)

with the addition of a compound table on top of the rotary table, the user can move the center of rotation to anywhere on the part being cut. This enables an arc to be cut at any place on the part.

Additionally, if converted to stepper motor operation, with a CNC milling machine and a tailstock, a rotary table allows many parts to be made on a mill that otherwise would require a lathe.

Rotary tables have many applications, including being used in the manufacture and inspection process of important elements in aerospace, automation and scientific industries. The use of rotary tables stretches as far as the film and animation industry, being used to obtain accuracy and precision in filming and photography.

Can any of you recommend a good online source of information on buying, setting up and using a Rotary Table. I don’t yet have one but I have a few projects in mind that will require one. TIA.

A Rotary Table that can be set on the milling machine table in either horizontal or vertical mode can be used in lieu of a Dividing Head (Especially if Division plates are available )

In my case this involves using adaptor sleeves in the lathe, which are then removed to mount the chuck, complete with workpiece, into the Rotary Table on the mill to cut the teeth. (Again, in my case, a small Myford fitting chuck is mounted on a 2MT arbor. In the lathe a drawbar holds it in place, and in the R T, an Allen capscrew and top hat bush pull it into the taper.

I fitted the Tailstock with two dowels to locate in the T slots of the mill table. They may need to be stepped. . I bored a 2MT stub arbor to a very close fit on the Tailstock arbor. In this way the Tailstock can be adjusted to exactly the centre height of the Rotary table, and the Tailstock, being located on the mill table, aligns the Rotary table along and across the mill table.

Hi Vic I bought a rotary table and three jaw chuck of the same diamiter to mount on top. The one thing I forgot to take into account was the chuck had three equally spaced mounting holes and the rotary table had four equal T slots so I had to make a mounting adaptor plate to go between the two. It wasn"t a problem but just another job and it slightly reduces the usable height under the spindle.

Vic - As a regular user of R/T"s the only thing I would add is look to a vertical and horizontal mountable version if possible and definitely choose a four slot table as opposed to a three. The four slot are much easier to set up on if the table area is small.

Here"s an example (though smaller in diameter than the table) on the MES but the same principle. BTW a set of small clamps using cap heads for bolts are invaluable on RT set ups where space is at a premium

It’s a bit of a minefield out there. Some RT tables say in the description the gear ration is 90:1 or 36:1 but some don’t mention it at all. Is there a clue of what the ratio might be by looking at the division markings on the hand wheel collar?

Vic, i hope you started by reading the dozens of threads on this forum for both rotary tables and dividing heads as the replies tend to intermingle subjects. Now I notice you are a major participant on here so I am probably preaching to the converted of course.

If you plan to do small jobs a grid of tapped holes adapter plate makes setting up vastly easier. The common import strap and stepped packing blocks are cumbersome at the ebst of times and, frankly, way too big for the samller breed of table.

Alloy tooling plate is probably the best material. On a 100 mm table M5 holes on a repeating 20 mm square with one in the middle 5 spot dice pattern would probably work well. My tables are bigger so I bought aluminium breadboards from Thor Labs, an optical laboratory equipment supplier, having M6 holes on a 25 mm 5 spot pattern which work well. Not cheap cheap but sufficiently inexpensive to outweigh the tedium of drilling and tapping lots of holes. If you make one best to machine tap with a good spiral point tap.

Tug shows some nice, compact clamps. My version is a little posher with a knurled thumb screw to set the height at the back having a free running pad at the bottom to protect the table or hole plate. More work for more swank but no realistic gain in function.

Vic, i hope you started by reading the dozens of threads on this forum for both rotary tables and dividing heads as the replies tend to intermingle subjects. Now I notice you are a major participant on here so I am probably preaching to the converted of course.

Buy the largest r/table that you can afford/lift/ and will fit your mill, small ,r/tables are ok when fitted with chucks but when it comes to clamping work direct to the table a lot of space is required for clamps,though extra space can be achieved by fitting a subplate to the table,secured by countersunk screws fitting into the t nuts,and then drilling and tapping the subplate with a suitable pattern of tapped holes. when I could no longer lift a very heavy French Dufor 12 inch table I swapped it for an industrial Taylor Hobson 10 inch table , I now use it on my Elliott 00 omnimill and though its a little large for the mill it will take most jobs and clamps,my small far eastern 6 inch r/table has not been used for many years ,generally too small ,

Re rotary tables, I have an HV6 clone from Warco. Many variants around, the word on the street being Vertex are better made than most. Mine"s OK. It has a 90:1 worm, does horizontal and vertical, and came with a dividing set of hole wheels and fingers. They"re important because most of us lack the memory, concentration and intellectual horse power needed to twirl a rotary table handle correctly for anything other than straightforward integer degree work. Hex head cutting is easy, but the operator needs mechanical help to do most gears. (An even better answer is a computer driven stepper motor.)

One reservation. The table is on the delicate side, fine for turning an angle, locking, and taking a cut. Using it to feed metal into a cutter, as when spoking a wheel, is likely to cause severe wear if done frequently and over-enthusiastically. If needed for that type of work, might be better to look for an industrial table. But beware, they"re expensive and although they take more abuse, they can be wrecked in this mode too. Nothing like busting a Bison to ruin your day!

Thanks for the tip Dave, yes that search is so much better! Sorry, another question. Folks have said four slots are better but how do you fit a scroll chuck with three studs to a table with four slots? I’ve seen a simple way of mounting on a three slot table without any adapters etc, just using studs and round nuts with holes for a Tommy bar.

I hope Simon doesn’t mind me posting this but it’s such a clever and simple idea. I’ve seen a RT at a good price but it’s got four slots so I’d be keen to know how to mount my Chuck without having to make an adapter. And why are four slots better anyway?

I have two 3 Jaw chucks mounted on backplates that are a bit larger than the chuck body which allows the backplate to be held to the table with tee nuts, a spigot on the backplate to locate in the table"s central hole make sfor easier set up.

Yep - Jason beat me to it but my set up is the same - chuck to plate, plate to table. Plate has locating spigot to fit table bore, chuck has locating spigot to fit a recess in the plate and the chuck bore.

Ditto with the four versus three slots - four allows more versatile clamping of parts when using table alone. Buying a three slot just so the chuck can be mounted is limiting the versatility for something that is not used that often - well not on the R/T in the fashion shown. Both Jason and I have R/T"s larger than the chuck body but you can still have a plate interposed even if the diameters are the same.

Those large tee slots however were cast in originally - anything but smooth so took a fair bit to clean up. I later added the degree ring and the stops - if there is one thing to improve an R/T it is to fit some kind of adjustable stop set up as they take all the worry of, and potential for, over movement to occur, something that"s easily done on a R/T

Thanks for the replies, food for thought. At the price point I’m currently looking at, despite any description, it may be interesting to see if one arrives with 3 or 4 slots! Out of funds at present so I’ll have to wait a while.

I have H/V rotary table and followed an article in MEW, making a stepper motor controller using an Arduino, not easy for me, got there with a lot of help from folks on "here" thank you chaps. How good it is when cutting a gear, NO losing count, or thin tooth, so after the purchase, I suggest you consider making a controller. John

Obviously, being a screw fit chuck, if using for radius cutting, the direction of table rotation / cutting forces need to taken into account, to prevent the chuck coming loose...

So far, with Tailstock support, have had no problems with unwanted movement when cutting gears (Table face vertical, axis horizontal ) Since gear cutting involves a full depth cut with SLOW feed , this seems to have worked, so far!

Years ago, before I learned CNC, I owned a Phase II 8″ horizontal/vertical rotary table that I purchased from Kap Pullen’s Getmachinetools.com store. He has them at a good price, BTW, and he’s a darned nice fellow to deal with as well as being a frequent HSM contributor. Anyway, its a nice little table, but I hadn’t done a whole lot with it for quite a while after purchasing it. As is so often the case, one day, a project landed on my doorstep and I was glad to have it.

Before I could get started, however, I had to make some accessories for it. Basically, I needed some T-Nuts to fit the table, as well as a little fixture that makes it easy to hold a plate up off the table through a hole in the center so you can machine it. The latter, what I call a “plate machining fixture”, was inspired by something similar I saw the Widgitmaster of CNCZone fame using to make Dremel clamps for his mini-router:

The Plate Maching Fixture and 3 Homemade T-Nuts. T-Nuts are easy to make: square a block to the proper dimensions, mill the side reliefs, drill, and tap. These are much smaller than the mill’s Bridgeport standard T-slots, so I made them myself and I’m using 1/4-20 bolts with them. They’re made of mild steel.

I turned the round spigot using the 4-jaw on the lathe. I’m making the fixture out of MIC-6 aluminum plate, which is pre-ground very flat on the sides. This is a 5 inch by 3 inch piece. I’ve clamped it to the rotab using my T-nuts and the regular mill clamps and step blocks. It is sitting on parallels to make sure I don’t cut into the table. You can also see how I’ve clamped the rotary table to the mill table using a big cast iron V-block I have. You can never have to many blocks with precision faces hanging around!

Having a 4-jaw chuck on your rotary table is mighty handy! Because it’s a 4-jaw, you can dial in the workpiece by adjusting the jaws until it is perfectly concentric with the table’s axis of rotation. The best way is to make an adapter plate that attaches to the back of the chuck in the same way that your lathe does so you can exchange lathe tooling with the rotab. Here is an example:

For the example, the chuck is threaded onto the adaptor plate, and then the holes in the adapter plate’s flange are used to bolt down to T-nuts on the table.

In my case, I bought a 4-jaw from Shars brand new, and simply drilled some through-holes in the chuck to mount to the table directly without an adapter plate:

First, you want to make sure your part is properly centered on the table. To do that, I clamp the table down on the mill table (no special place is needed), put my Indicol indicator holder on the mill spindle, and find some round feature on the part to indicate on. For example, on the plate milling fixture above, indicate on the round boss, or on the center hole. Spin the table and bump the part in until spinning the table doesn’t move the indicator.

Second, locate the center of rotation directly under the mill spindle. You can simply use the X and Y table handwheels to do this. Use that Indicol to indicate off of a circular feature you want centered under the spindle. Turn the indicol around on the spindle and adjust the handwheels until the indicator stays put relative to the spindle position. A Blake Coaxial indicator will make this last even simpler.

When you’re rounding partially by cranking a part around on the rotary table, it’s really easy to go a little too far and screw things up. The answer is to drill the end points to make the exact stopping point on the rotab a lot less sensitive:

Centering with a Blake indicator is really fast, but what if you don’t have a Blake, or worse, what if your mill is too small to accomodate one? Here is a nice solution I found on a German site. This fellow has made an ER collect fixture for his rotary table, and has taken care that when installed on the table, the axis of the collet is aligned with the table’s axis. He can then place a dowel or other straight pin in the collet and line up until it will go into a similarly sized collet on the spindle. Nice trick! It’s similar to how Widgitmaster showed me to align a drill chuck on a QCTP to the lathe centerline with a dowel pin held in the lathe chuck.