Tail Stock Die Holder

First off -- if the die is otherwise free to rotate in the tailstock ram, and the handle is long enough to contact the bed ways, add a layer of something like Delrin (acetal) or perhaps Nylon to keep the swinging handle from dinging the ways.

Are you planning to cut threads under power, or to manually turn the die holder? If the latter, slip fit will make it easier to shift the handle from one hole to the next to enable you to swing it, shift handle, and swing again.

Only reason to make them threaded instead of slip fit would be if they were shorter than the reach to the bed, and you were going to put in two or three of them to allow you to switch your hands from one to the next.

Or -- if you are planning to cut under power, and the handle is planned to rest against the bed (properly covered with a non-dinging surface.)

Personally, if you are going to cut under power, I would make the holder capable of sliding towards the headstock a short distance, and a pin locking the holder against rotation until you pull forward a short distance -- thus making it like a releasing tap holder for a turret lathe. (For dies, the turret lathe would use something like the Geometric die head -- sort of like a 4-jaw chuck with the jaws being the chasers to cut the threads. When the holder is pulled a short distance towards the headstock (once the turret reaches its stop) the chasers all pop out releasing the threading cutters from the threads in the workpiece, allowing the workpiece to keep rotating while the die head is retracted.

BTW It *should* be possible to mount such a Geometric die head in a boring bar holder for a quick-change toolpost. If you position it truly on center, you can feed it by hand using the carriage handwheel -- and with a bed stop you can cut equal length threads on multiple workpieces. (Or -- you could feed using the threading feeds and release the half-nuts before you reach the end of the threads -- once you have a few threads, it will self feed. I've never tried this, because I do have the bed turret to use with my Geometric heads.

Enjoy, DoN.

Thanks Don. I guess my main thing is I just wanted to keep the tommy bar with the tool. I'll stick with a slip fit hole and be done with it then. Well, probably three of them.

It has been made, and used now. Simple construction. Pin and sleeve. Set Screw to hold die. Slip in tommy bar. Four holes for tommy bar to maximize ability to work it. The business end was simply ID turned to 1" and some slop was left (.01" apx) between the pin (.75/.76) and the sleeve. I really wanted an MT taper on the back, but I just am not good enough to cut that smooth, and then harden it and get it all just right. So instead I just turned the fixed end to 1/2" and clamped into my taper mounted drill chuck. Still not totally happy with that (it works, but, but takes up a lot of the total working room of a small lathe) I thought about maybe putting it into a

1/2" MT tool holder. Of course that requires I turn it perfectly or accept even more slop in my sleeve. I thought about a collet holder, but then that drives up the cost. Then finally it came to me, and will allow me to use my die handle tool on any taper machine easily. There are MT1, 2, & 3 tapers with a 1/2 20 end for a threaded drill chuck all over the place for about $5.. Problem solved. No real precision machining required, and pretty consistent overall tool center even on a cheap lathe. Drill and tap the back end to 1/2-20.

Now that I have done one of these and come up with a cheap near universal solution I don't see why those selling them in the states are so expensive.

And of course I learned that it would have been better to make it out of

1144 for a better looking finish instead of the scrap (mostly 1018) I had laying around. Small pieces of 1144 are not much different in price than small pieces of 1018, but I had the 1018 on the shelf.

Easy way to duplicate Morse, B&S and so forth tapers is to set up between centers and establish your compound or taper attachment angle using an existing article of taper shank tooling as a master.

centers and establish your compound or taper attachment angle using an existing article of taper shank tooling as a master.

These might give you some ideas

Yup!

This is a similar item to what I went with. About the same price. I stuck with the 1/2-20 because I can also get MT1 and MT3 with 1/2 20 from the same source. In the future I'll be able to swap the taper quickly and use my die holder on a larger lathe if I ever get one. My 8.5 by 18 also has an MT2 taper so for now just one does the trick.

Hopefully I will remember that when I need to know it. Thank you.

I am thinking about making a variant of the theme using a straight shank ER collet holder for tapping. I have some further thoughts on that idea too.

message

220-1514

Not to change the subject but in many cases, a person can buy chinese tooling items for less than he can buy the raw material.

This appears to fall under the "law of unintended consequences"...while placing duties on import steel in order to protect domestic production seems at first to be good policy...

--if you don't also place duties on the finished product(s), then the steel industry AND it's customers BOTH end up going down in flames.

This does appear to be the case. I had several projects in mind and just the material cost/cut charges for the big pieces, omitting my labor and the small pieces, e.g. screws, nuts, washers, bearings, etc. was more than the finished project delivered to my house would cost.

One problem is that I don't know how much of a domestic commodity steel (or aluminum) industry we have left. Not everyone can afford or needs HY150 when 11L44 will do.

Why do you need to harden it? Dead centers (solid ones used in the tailstock) are hardened for good reason. The old meaning of "live centers" (solid centers which fit in the headstock spindle and rotate with the spindle) are normally dead soft -- so you can true them after inserting immediately prior to use.

For a *single* machine -- make it a slip-fit over the tailstock ram. About as short as you can get. (You probably would need to start with a large diameter stock.

For moving between multiple machines, the screw-in (or for that mater, Jacobs taper) drill chuck arbors are a good approach. (I would consider the Jacobs arbors to be closer to true. :-)

[ ... ]

Congratulations.

:-)

And you could probably get an even better finish with 12L14 -- which I love to turn. :-)

Enjoy, DoN.