Tailstock Mounting Question

[Robert Arnold]

I am looking for ideas on how I could mount an item in my tailstock and place tension on it. I will use a 4 jaw scroll chock or a collet chuck in the headstock but I would like to attach the other end of a long spindle to some type of fixture in the tailstock that would allow me to put tension on the item. I have a Oneway 1640. Any ideas are appreciated.

Thanks, Robert
The Dog House Workshop

 

[Gynia]

A Jacobs chuck with a drawbar.

 

[Robert Arnold]

Where would I find a drill chuck with a fixed MT3 and threaded for a drawbar that would fit through a Oneway tailstock? Have you ever tried this? I was also asking the question to find out if there are any potential problems or issues that could arise by using the tailstock this way. I will be puting a small amount of tension on the piece by backing the tailstock spindle out once the piece is mounted.

Thanks, Robert

 

[wwlewis]

It is not quite as simple as a drawbar with a jacobs chuck if you expect to turn with the piece in tension. The Oneway live center has a large enough hole with the pin removed to put in a piece of all thread with the end peened over. This can be run through the live center and out the back of the tailstock and fastened. With an adapter from Oneway or one of the other suppliers a chuck can be attached to the live center and tension applied.

Not exactly simple, but both ends should be secure.

 

[David Wilkins]

The oneway live center has a threaded point, but you would again need to restrain it, I can't remember if it is threaded in the taper though. I know people do this, and the jacobs/drill chucks are typically in the headstock with a draw rod.

 

[Bill Boehme]

Where would I find a drill chuck with a fixed MT3 and threaded for a drawbar that would fit through a Oneway tailstock? Have you ever tried this?

You may not be the first person ever to have a need for this, but it is probably rare anyway. Keep in mid that because wood is compressible that it is possible to creep enough to relieve the tension just as it is possible to creep and relieve a compression load if not bottomed out in the chuck or against a shoulder.

Drill chucks and tapered arbors are sold s separate items. One end of the arbor will have a taper to match the chuck -- often a Jacobs taper (JT-33 and JT-6 are most commonly used for the type of drill chucks that we would be using). The other end could be a MT-2 or MT-3 whichever your lathe uses. Having said all that, the idea won't work anyway. First of all this type of arbor comes with a tang on the end since it most commonly is used in a drill press. Even if you had one drilled for a drawbar, remember that the other end that is mated to the drill chuck has nothing to restrain it from being pulled apart. I would guess that rwarnoldjr has not tried this idea.

I am wondering why you might want to have a spindle in tension. Remember that stress risers concentrate at abrupt transitions, most significantly at the bottom of V's.

It is not quite as simple as a drawbar with a Jacobs chuck if you expect to turn with the piece in tension. The Oneway live center has a large enough hole with the pin removed to put in a piece of all thread with the end peened over. This can be run through the live center and out the back of the tailstock and fastened. With an adapter from Oneway or one of the other suppliers a chuck can be attached to the live center and tension applied.

Not exactly simple, but both ends should be secure.

This would be a workable solution if not for the fact that by doing this, the live center is now being constrained from revolving.

The oneway live center has a threaded point, but you would again need to restrain it, I can't remember if it is threaded in the taper though. I know people do this, and the jacobs/drill chucks are typically in the headstock with a draw rod.

I just happened to be checking my Oneway live center this evening and it does not have a thread hole. However, the hole is about the right size to thread with either a 5/16-24 or 5/16-18 tap. The live center may be hardened steel, so be careful. The other thing to consider is whether a threaded rod of that size will go through the hole that runs through the tailstock. It could on my Delta 1440, but not on my Robust.

 

[Joe Greiner]

If the workpiece is short enough, I'd consider 5/16 all-thread glued in an end hole, and extending through the empty quill; with double nuts at the handwheel, and a thrust bearing to restore live-center capability. If the workpiece is too long for that, you might have to remove and manipulate the tailstock for final re-installation. Alternatively, use a transverse wood screw (or two) to lock the all-thread in the end hole. Either way, the end material is waste.

Since the handwheel doesn't move back with rotation, use the inboard double nut to set tension, and the outboard one as a lock nut.

"Why?" is a separate question entirely.

[If this is related to your other inquiry about "long thin spindles," add a larger waste block to provide for the end hole.]

 

[Robert Arnold]

Thanks everyone for the comments so far. One of my first ideas was also the drill chuck mounted on a MT3 but it would need to be fixed to the drill chuck by threading or some other mechanical means that would prevent it from pulling out if tension were placed on it. It would also need to be threaded in the end of the MT3 to take a draw bar that would fit through a Oneway tailstock. I couldn't find this set up so that is why I was asking this group. I would prefer to do all of the work for the project I am considering on the lathe. This post is connected to another that I made recently concerning turing long thin spindles, 1/8" to 3/16" diameter 18" to 24" long. One of the recommendations made in the other post was to use a dowel plate and that would probably work but I would like to complete as much of the project as I can on the lathe. The Oneway live center has a through hole but it is not threaded. It may be an option to have this threaded but I wnated to see if there were any other ideas from the group. One of my other concerns and this has not really been addressed yet is will using the tailstock to place tension on a piececreate any problems with the tailstock or the item being turned.

Thans, Robert
The Dog House Workshop