[boxmaker]

Hi All

I have a 4" Soba rotary table and was wondering if it is possible to fit my 3 jaw lathe chuck to it using a morse taper and threaded end, the idea is to put the morse taper into the RT after centering and then screw the chuck to that.
The problem is finding the 2 morse taper with threaded end to suit my chuck.

Any one know where to get one 1" 8tpi.

cheers

Ian

[M250cnc]

Hi Ian,

I doubt if you could get one off the shelf, but i could make one for you.

Is this always going to be attached to the RT ? if yes there are better ways to do it.

Phil

[boxmaker]

Hi Phil

Thanks for the speedy reply, Yes it is for the RT only.

I have seen chucks with back plates that get secured to the RT but I just thought if the RT was centered and I added the chuck and back plate I would have to re-center again.

I happy to hear your suggestions for mounting it.

Cheers

Ian

[knudsen]

Usually the back plate does the centering.

[boxmaker]

Oh I didn't know that. The only thing is I don't think there is a back plate for my chuck, so might have to buy a new one but I really want to use the lathe one as it seems abit of a waste .

Ian

[M250cnc]

Hi Ian,

I meant will it be permanently attached, or only attached occasionally ?

Phil

[boxmaker]

Oh sorry Phil, occasionally just to keep my options open.

Cheers

Ian

[boxmaker]

Hi Phil

I should have mentioned that I may also want to use my lathe face plate on it aswell so the 2 morse taper with threaded end would be very helpful.

Ian

[M250cnc]

Hi Ian,

The best way to do this is a plate "That has a recess" that locates on the OD of the RT it will be fixed to the RT by cap screws into T Nuts the chuck/face plate can then attach firmly, the morse taper will be a flimsy way to do it.

Phil

[boxmaker]

Hi Phil

Ok thats sounds good, how is the chuck attached to the plate? and could you make me one of these.

cheers

ian

[M250cnc]

Hi Phil

Ok thats sounds good, how is the chuck attached to the plate? and could you make me one of these.

cheers

ian

1" x 8 tpi

Phil

[knudsen]

Ian, I would try to find a plate for the RT, then adapt the plate and/or chuck to mount it centered on the plate. Might be easiest to drill and tap the back of the chuck to match the plate. Might be most accurate to make a threaded part to fit the chuck to the plate. For a 4" RT, you can get a decent plate and chuck from LMS, but of course, you want to make sure it will fit the RT. You also should be albe to make a plate fairly easy on your lathe, from mild steel or CI. I believe "grey" CI is preferred. If you have another material on hand, I would try that, maybe even Al. If nothing else, you get practice on what you have befor you buy the CI. Just make the plate larger than the chuck so you can drill it for the bolts going into the RT/T-nuts. Maybe make a nub that sticks out, threaded or tight slip fit to center the chuck on the plate, then drill/tap/bolt it in place while the chuck is on the back plate. You will also want a nub that goes into the taper in the center to center the plate on the RT. Let us know what works for you!

[boxmaker]

Hi Phil

Here are a couple of pics - one of the lead screw nut and the other of the key mortice (the one I dropped)

The righthand handle has 2 bearings but the lefthand has only one, there seems to be a space for a second but there is only one why would that be?

let me know what you think about the backlash removal if its possible.

cheers

Ian

[M250cnc]

Hi Ian that nut, looking by the Y axis is not fixed it just floats in the pocket, if that is the case, take out the two adjusting screws and make that slit lower.

I do this by using more than one hacksaw blade so put two or three that fit in the slot and just cut lower, this will allow the two halves to come together easier, you should adjust the backlash on an unworn part of the leadscrew.

Re the bearings i believe these are in three parts, best described as two washers with a radial groove, with a set of ball bearings between them.

On the end with two bearings you tighten the handwheel nut up so that there is no play but not binding, the end with one bearing again just tighten the handwheel nut so that there is no play and no binding.

Now if you incorrectly adjusted those nuts on the handwheels that would give you the impression that you had backlash that is why it just appeared, what you had was endfloat.

Re the key just fit anything in there temporary and when the mill is running correctly you can make a nice one.

HTH
Phil

[boxmaker]

Hi Phil

Yes that helps and clears up a lot, the nut doesn't float it has to bolts on the lower cross slide that hod it in place( but I'm not sure if these are lightly tightened or fully)

I tried cutting last night as a test and still have that rippled cut, there seems to be a slight rocking effect in the table and if I tighten the gib to remove this the travel is too tight - if I move the X to the full end or near the full end of travel there is play (up and down) I'm wondering if I damaged the cross slide when I had to hammer out the gib - what do you think?

The bad news is I might have to replace the slide and gib as the rippled cut is unacceptable.

cheers

Ian

PS I just want to say you have been a great help THANKS!