rotary table use question

Grant, The setup I use involves the use of a plate that the chuck bolts to. If you are using a chuck with camlock pins then they must be removed. Then either use the tapped holes that hold the pin locking screws or better yet drill and tap new holes close to the OD of the chuck. The plate that holds the chuck should first be machined on one side so that you have a flat surface and a spud sticking out that registers in the hole in the center of the rotary table(RT). Drill and c'sink three or 4 holes in this plate to screw into the chuck and another set of holes to bolt it to the RT. Wether you use three or four holse depends on the number of slots in the RT. So a six slot table would get three screws and a four slot table four screws. Or a big honkin' table with twelve slots lets you choose. The chuck I use has a register machined in the back to accept the plate. I bolted the plate to the RT and then used the RT to mill a boss to fit in the register in the chuck. This method helps to insure that the plate is true to the RT. The register in the chuck was put in by me and runs true to the jaws. I also have another chuck that is adjustable that I can put on the RT but usually the work I do on the RT doesn't need to run truer than .002 so the non-adjustable chuck gets most of the use. BTW, if you want to know how to modify a chuck to be adjustable let me know. It depends on how the chuck is made what the exact mod will be. Cheers, Eric

What I did on my 6" PH2 table is make a spindle with a thread that matches my lathe chucks. A MT2 spindle with 1.5 x8 threaded end and a socket screw Wwasher on the other end. Simple project, just have to remember to rotate the RT so the chuck doesn't self feed into the cutter and unscrew itself. It didn't have enough room to clear on the bottom end so if it's fastened vertically on the mill table i have to use some washers to get clearance, horizontally there's no problem. I made it in two pieces and silver soldered the threaded end on the spindle.

DE

I bought a little Bison 3-jaw for my 4" rotary table from New England Brass. Bob also sold me, at the time, a little mounting plate with holes for the

3-jaw in the back and four holes for mounting to the table on the side. No difficult to machine.

Boris

I just bought one of these:

I haven't checked it for runout yet. It probably isn't rigid enough for rotary machining but then my 6" rotary table itself didn't take well to cutting the T-slot in a swivel vise base.

Maybe you could turn a recess in a plate so it fits snugly over the table, then cut the top to fit the register recess in the back of the chuck.

jw

Hmm .. that gives me some ideas. My little 6" Yuasa RT has a round bore but it has an MT2 sleeve installed, and I guess I'd have to disassemble the unit to remove it, since there's no way to knock it out from the back (bottom). I tried some of my MT2 tooling on it, and most of it bottoms out. Have to have a real short MT2 shank.

I think I'll try removing the sleeve, then turn a plate like Eric says which has a boss in the back which closely matches the bore and has 4 holes for mounting to the RT's table slots, and 3 holes for mounting a 3-jaw chuck. Or maybe I'll just try my little 4-jaw chuck for awhile and get used to dialing parts in.

Grant

I think several methods are used. I have periodically wondered if I couldn't make a set of jaws to ride in the slots of my RT. I've made some sketches but never gotten any farther. Wouldn't be as accurate as using a true chuck but it doesn't seem like it would be too difficult a project and the low profile would be very attractive in cases where headroom is at a premium.

I think that's an excellent idea. You could buy a 4 jaw chuck and mod the T slots to fit. So use the 4 jaw when you can and remove the jaws when needed. I'm gonna check my table right now. Thanks, Eric

============================================== Put some color in your cheeks...garden naked! "The original frugal ponder" ~~~~ } ~~~~~~ } ~~~~~~~ }

Ah, that would be

in case anyone doesn't want to navigate..

Jeez, Roy, that RT table has 6 slots! A 3-jaw with plain back would just bolt right down to it. I'd do that except my table has 4 slots. Nice job, though a pic of the actual adapter plate would be better than all the wordage ..

GWE

Hmmm... not so fast. It would have to be a different sort of design, but I think something rather similar could be done. Not quite as strong or as accurate but still usable and very low profile.

OK, I'm curious - what do you use it for? Bob

Well. I just compared the jaws from an 8" 4 jaw to the 10" RT. The jaws have a slot that's .394 wide to keep them in the chuck. The corresponding part on the RT is .500. If this was milled to .394 the jaws would slip in. But here's the rub: The screw that moves the jaws is of such a large diameter that to machine a groove deep enough to accommodate them would seriously weaken the RT. It's still a good idea though. I just need to find or build jaws with a smaller screw. One possibility would be to use a short screw so that only short, deep slots would be needed. Or, maybe turning a screw to fit the threads in the jaw and milling enough off so that it ends up as a half moon shape. Then tap this with a thread that will fit in the space available. That way the original thread would only be used as a key. I still like your idea Dave. Thanks, Eric R Snow, E T Precision Machine

I don't have any pictures handy but I've got a large face plate which has "bolt on" jaws on it in storage at the moment. The jaws fit in the T slots and the screw is up above the surface of the face plate. They have a limited travel but with the T slot you can place them close and then adjust with the screw on the jaws. Something like this would solve all the problems listed above.

Wayne Cook Shamrock, TX

I recall the 48" face plate that came with the sliding gap bed LeBlond lathe I used to run was so equipped.

Harold