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Tailstock Drill Chuck Question

Robert Arnold

Robert Arnold

Joined
Oct 28, 2008
Messages
67
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Location
Bushwood, Maryland
Website
thedoghouseworkshop.com
Does anyone know where I could find a 3MT drill chuck that has the arbor bored to accept a drawbar. I also need the chuck to be threaded onto the arbor or an integral shank. I need to mount the drill chuck in the tailstock then I will place some tension on the chuck which is why I need it fixed to the arbor and a drawbar.

Thanks, Robert
 
Are you just applying tension to a static piece. You won't be able to rotate the piece in a standard chuck stuck in the tailstock especially with a draw bar. Even without a draw bar the rotating morse taper would tear up the original morse taper.
To apply tension to a spinning turning you need some sort of bearing assembly. I have not tried it yet but the Oneway love center might be able to be threaded to accept a draw bar. Then you could buy the Oneway chuck adaptor for the live center. that would allow you to put a chuck on the live center and apply tension to a turning. At least I think it would. I have not tried it yet. I have a powermatic live center and may see if I can tap threads into it.
 
I checked my Oneway live center and foiund that it is NOT tapped. I experimented a bit to see if the end could be reamed and tapped. I found that it is hardened and that a regular highspeed tool bit will not scratch it. Too bad, because the bore is almost large enough to take a 3/8 thread.

Dennis
 
Oneway live center with center point removed
Oneway live center to chuck adaptor
draw bar with nut and bearing on the headstock side of the tailstock and a washer and nut at the tailstock hand wheel.
Mount chuck on the live center.

This might work.
 
From what you said, I assume that the tailstock is a MT3.

Drill chucks and Morse taper arbors come separately. They are commonly used in drill presses, milling machines, and other machine tools. High precision drilling machines usually use cutting tools that have tapered shanks which leave out the middle man that only add to alignment errors.

For the size chucks that we commonly use, the chucks usually fit either a JT6 or JT33 arbor and the other end that goes into the machine spindle socket fits your machine spindle size which is most commonly MT2 ot MT3. (JT stands for Jacobs Taper).

One of the places where you can get them is Grizzly.

Oops, I overlooked the part about you wanting one that is threaded for a draw-bar. That might be a bit more difficult. If you have problems with things slipping in the tapered socket. it might be the result of damage cause by an arbor spinning and galling the socket. If so, it would be worthwhile to repair the damage before it propagates to all of your tailstock inserts. The odds of finding exactly what you want is very low. You might need to grind the tang off the back end and then drill and tap the hole yourself.
 
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Although I found that the Oneway live center is not tapped and is too hardened to ream and tap, it occurs to me that there is a simple work-around. Epoxy a 1-2 inch piece of 5/16 inch aluminum, brass, plastic or other workable material in the outer end of the live center, and drill and tap it to fit a 1/4 inch all-thread drawbar. You will still be able to use the Oneway knock-out bar when needed to remove the center, and if you ever need to, you can easily drill out the insert without damaging the hardened live center. I do not know how much thrust the Oneway live center will stand in the outward direction, but I expect that it is much less than the force needed to strip out the epoxyed filler piece.

Dennis
 
I probably should have been a little more explicit about what I want to do. I would like to mount a very long thin piece of stock. In the headstock I have a Vicmarc chuck with pin jaws. I want to mount a drill chuck in the tailstock and tighten this on the opposite end of the piece and then back the tailstock out to place a slight amount of tension on the piece. The lathe will be turned on with the piece mounted like this. Most drill chucks that I have found have a press fit between the chuck and the MT3 arbor so this will not work. I have found MT3 arbors that are threaded for a drawbar but I have not been able to locate one that has a threaded end that could screw into a drill chuck or a drill chuck with an integral MT3 arbor that is threaded for a drawbar.

Thanks, Robert
 
Robert, If you have a Oneway live center, you can tap the hole -- I have so I know it can be done, but you might need to ream the chrome plating off first before drilling for the tap size -- and don't use cheap imported taps that can snap off. DAMHIKT Oneway has threaded spindle adapters that will screw onto the rotating end of the live center. You could then mount a chuck with pin jaws onto the live center adapter.
 
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John Lucas is correct in that the setup you are describing is not meant to rotate. You need a bearing in there somewhere. The drill chuck and draw bar in a tailstock does not spin.

Penn State sells a rotating chuck adapter on which you can mount a scroll chuck and it will then rotate as desired. There are others as well. Don't know if it is tapped for a draw bar though.
 
Robert, while I and others have described ways in which you can achieve a freely rotating tailstock drill chuck, you may still have problems. Depending on how thin the spindle is you may find that the inertia of the tailstock system will cause the spindle to twist off when starting or stopping, or that the rotating friction of the tailstock bearings alone will do it. If you have some way to test this with your present equipment without a draw bar (no to apply traction for this test), you may find that you are wasting your time. 🙁

Dennis
 
Another consideration, and you don't need to ask how I know this. When you start up the lathe the wood itself has to drive the chuck on the other end. If you don't start the lathe slowly it rips the wood in half. Need I say more 🙂
I was going to pursue using 2 chucks and hooking the together with a set of gears of chains so the headstock chuck would drive the tailstock chuck at the same speed. I never needed it bad enough to actually build that contraption. My skills have improved to the point that I can turn pretty long thin spindle with string supports and my fingers so I haven't needed the tension device.
 
Go to The Little Machine Shop they has a #2 mt with a drill chuck mounted on a bearing for doing exactly what you want to do. I use one to do thin stem goblets. I believe their around $45.00. Don't know if their threaded I only use the lightest of pressure.
If you call them they can probably put one on a #3mt. Their really nice people out there.
 
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