Post By eddieirvine
Mounting 3 jaw chuck to rotary table!
I bought a rotary table for my mill, and I am going to use my smaller 3 jaw chuck I had mounted on my lathe to mount to my rotary table! the rotary table has a center morse taper # 2 for using a center when in vertical mode! along with a center! I would like to mount my three jaw so I don't have to mess around centering it on the rotary table! back plate on the three jaw is 1 1/2 x8 tpi which is what my South Bend A lathe is. I am thinking it would be nice to use the number 2 morse taper that is in the rotary table allready, so I am thinking maybe an adapter that is a morse taper # 2 on one end and a 1 1/2" x 8 on the other being one piece!that way I can just screw the chuck right on to the rotary table! any ideas from you guys let me know, just trying to make an easy way to mount this when needed for smaller round stock, for milling or drilling bolt hole circles! thanks Eddie
It sounds good on paper, but if the thread on your locating widget bottoms out in the chuck and registers on the pilot like it's supposed to, then probably the MT taper will either be not deep enough or up too high in the rotab center socket, so that wont work.
OTOH, if you seat the male MT end correctly in the socket, and screw on the chuck enough to touch the table, any cut you take will probably loosen the whole thing up.
Your direction of thought is good for easy location but I think you'll need to have the chuck secured to the table some way regardless.
You are doing the same project I did.
I turned a shaft and threaded it to mount my chuck onto, make sure it is big enough in diameter that a good shoulder is left for the chuck to bottom out on. The whole shaft is ~5" long. I then welded a plate onto the other side that is ~2" bigger in diameter than the shaft. That gave me a place to put my hold downs onto. Make sure you leave enough room to get your hold downs in under the chuck.
BTW, after you weld the plate onto the shaft make sure to mount the shaft in the lathe and turn the bottom of the plate perpendicular to your shaft.
Then drill and ream a hole into the end of the shaft that the plate is on. I took an old reamer that has a MT2 on the driving end and cut off the reamer part and turned the OD to match the hole that I drilled and reamed into the chuck holding shaft. The shaft is straight on one side and MT2 on the other.
All I do is put the MT2 shaft into my rotary table, slip the threaded chuck holder onto it so it is now centered in the rotary table and put on some hold downs on the plate that is welded onto the chuck mounting shaft.
I hope that all makes sense. Takes less time to install then describe in words.
Ferrous---- I did think about that, if I could make it just a snug fit on the tapered part that fits in the rorary table I was thinking of making a flange on that one piece adapter to be able to put about 4 flat head allen bolts in and bolt it to the rotary table! still throwing ideas around in my head!
And mg81---- sounds like a good idea you came up with for the hold downs! thanks for that I am looking for ideas like that and will keep yours in mind thanks!!
You mean like this?:
RDG Tools - Online Engineering Tools 2mt Boxford Chuck Adaptor "For Rotary Tables"
(main page is at: Boxford Lathe Users Page )
Boxford is a UK South Bend clone and uses 1-1/2"x8TPI spindle thread too (I use Boxford faceplate etc. on my South Bend).
Yes Jim just like that! I didn't even think about looking there! I just bought a nice collet chuck from them that takes R32 collets which I allready had and there R32 collet chuck was Excellent quality .005 run out or none! thanks I will check them out!
The problem Ferrous described about the MT being to high or low is the reason I did not make something like what RDG was selling. If you were willing to spend the time to get the height right that would work out (though I would be worried the taper might slip and spin and get things out of alignment).
With the set-up I described I made sure the hole in the bottom of my threaded chuck shaft was deeper than it needed to be (i.e. the the MT shaft does bottom out in the threaded shaft). This way I did not have to worry about how far my MT shaft went into my rotary table. The MT shaft only provided x-y axis alignment. The table of the rotary table indexed the z axis. Hope that all makes sense.
Last edited by mg81; 12-13-2011 at 04:57 PM.
Here is a photo of what I made sitting on my cheap Chinese rotary table. Obviously no hold downs are in place, but you can get the idea.
If I had to do it again I would make the shaft ~1" shorter, but I wanted to make sure I had enough room to get the hold downs installed. I also figured better to give myself more room instead of less in case some future job required more clearance.
(Also I would have done a better job decreasing the parts before I welded. My god the porosity of the weld from the oil contamination is embarrassingly bad.)
You are right about getting the morse taper correct! that has been in my thoughts about this set up! I have thought about it for a while and I think would want to make this as short as I could, also I am not real concerned about getting the morse taper fit really tight just a good snug fit, and have a flange like you do and just drill about 3 holes in that flange for some allen flat heads and drill and tap the rotary table so it can be bolted down and no chance of moving! so basically the tapered hole in the rotary table would be to line up the adapter not really do any holding the flange and the flat head allens would be bolted down to the table! best set up would be just so the tapered shaft morse #2 would fit so the flange could pull it into the taper flush with the rotary table top! would take a bit of fitting to get it just right but can be done! to me that would be the ideal way to get it made, if the morse taper was not so hard to turn you could machine it until it fit just right but it would have to be indiacted in to run true and they are a pain in the @#%$@#% to make with the right angle on the compound! for this set up it would be better if the hole in the rorary table was not tapered it would make the whole job an easy one! but if the table is needed for vertical work the tapered hole is handy!
Why dont you just buy an el-cheepo Chineese #2MT-to-Jacobs chuck arbor, and turn down the Jacobs end to some convenient straight diameter.
Then get a round plate an inch bigger than the chuck body, and attach a round pilot plug on center to fit the chuck (forget about the threads).
Ream a center hole in the plug the same size as the arbor you just altered.
Bolt the chuck to the plate.
Insert the MT locator in the rotab, drop the chuck & plate assembly over the "pin" that is sticking up, and strap clamp the chuck plate down. (or cut some U-slots into the plate to match the rotab table's T-slots).
I have purchased the rotary table adaptor from RDG and used it several times to attach a chuck to the rotary table. It works perfectly and cost 13ukp (about $20) but I do not know what shipping costs would be. This might save you a lot of work.
BTW, I was talking to the owner of RDG at the UK Model Engineering Exhibition this past weekend and, as we know, they now own Myford and have started trading Myford parts as a separate company. He told me that orders are flying out the door, but mostly overseas - very little going to UK! Seems we Brits have fallen out of love with Myford - but as I own an SB I look from the sidelines.
My adapter also lets me use it on a spot that is not the center of my rotary table and it can also be directly put on my mills table.
Not saying that you should not buy the commercial adapter, it looks to be a bargain if it will work for your table and chuck. But if I was going to spend the time to make something I would make it is universal/multi functional as possible.