Tail stock worn quill.
Tail stock worn quill.
Does anyone have thoughts on repairing the morse taper on a worn tailstock? Still holding drill chucks centers etc but under a load with a live center for example I'm able to see significant movement. Is this something to bore, or not a good idea to try at home? If so any suggestions on someone that's able to? I thought about a reamer also. I should mention of course not able to buy this quill or if I did find one it'd be crazy money I'd imagine, the last time I checked on parts I was connected to causing maybe they bought out Harrison I don't know. The lathe is a Harrison 15, I think 15x50. Thanks
Re: Tail stock worn quill.
Hi There,
I am unclear as to what your problem is. Is tooling not seating
properly in the taper? Or is the tailstock ram (sometimes called
the quill) moving inside the casting?
If it is the taper, you can buy a Morse taper reamer and freshen
the socket enough to get tooling to seat properly. The one problem
with that is the socket will be deeper and your tools will sit deeper
in the ram. This generally isn't a problem except your ram may not
return to the zero mark on the ram before it ejects the tool.
Good Luck!
-Blue Chips-
Webb
I am unclear as to what your problem is. Is tooling not seating
properly in the taper? Or is the tailstock ram (sometimes called
the quill) moving inside the casting?
If it is the taper, you can buy a Morse taper reamer and freshen
the socket enough to get tooling to seat properly. The one problem
with that is the socket will be deeper and your tools will sit deeper
in the ram. This generally isn't a problem except your ram may not
return to the zero mark on the ram before it ejects the tool.
Good Luck!
-Blue Chips-
Webb
-
John Hasler
- Posts: 1852
- Joined: Tue Dec 06, 2016 4:05 pm
- Location: Elmwood, Wisconsin
Re: Tail stock worn quill.
A reamer is best, but I've had good luck with the following procedure. First, clean the socket thoroughly with strong solvents and steel wool (be sure and get all the steel wool out.) Find a known-good, new or nearly new taper. Blue it up, put it in, wiggle it a bit, and take it out. Inspect it to get an idea just how bad the problem is. If you are lucky the cleaning will have done the job.
If cleaning didn't do it, use double-sided tape to attach two or more rectangular strips (not triangles!) of sandpaper to the taper. They must not overlap. I suggest starting with nothing coarser than 320: coarser paper takes up too much room. Blue up the inside of the socket and have at it until all the bluing is gone, then move to finer paper. I've never gone beyond 600.
Now check the socket again with bluing and the bare taper. If you want to get tricky you can tape small squares of paper to the taper and try to work down specific high spots.
This has the disadvantage (among others) of not reaching all the way to the small end.
If cleaning didn't do it, use double-sided tape to attach two or more rectangular strips (not triangles!) of sandpaper to the taper. They must not overlap. I suggest starting with nothing coarser than 320: coarser paper takes up too much room. Blue up the inside of the socket and have at it until all the bluing is gone, then move to finer paper. I've never gone beyond 600.
Now check the socket again with bluing and the bare taper. If you want to get tricky you can tape small squares of paper to the taper and try to work down specific high spots.
This has the disadvantage (among others) of not reaching all the way to the small end.
-
928gene928
- Posts: 42
- Joined: Wed Jul 28, 2010 9:55 am
Re: Tail stock worn quill.
I agree with the others who replied with using a reamer. If the taper is not you problem, and the quill is loose itself in the tailstock casting, I have used hard chrome to build up the OD of a worn quill with good success. Recently repaired a worn tailstock on my old Lodge & Shipley lathe using this method, and it is now like new. Good luck with your repairs.
Re: Tail stock worn quill.
At a guess I'm thinking one or more somethings has spun in your tailstock Morse taper Joshua? If it's a Clausing or Harrison that taper may or may not be hardened and ground. If it is a standard MT reamer won't touch it. If it's soft then as others have said it should work fine. But you only want to take the barest minimum to clean up the taper. A few thou cut and your male Morse tapers will seat a lot further into the female taper. It doesn't take much before the ends of your Morse taper tooling will bottom out in the hole before fully seating themselves into the taper. And then all the tooling will need shortening before it will work. Usualy a worn internal tailstock MT means the tailstocks bore and shaft is worn enough to be sloppy as well. There's been at least one thread over on the Practical Machinist forum about doing a proper job of correcting all that and it's not exactly easy or cheap and it's a great deal of work. Boring the taper could work if everything was set up perfect and you have a lot of experience. Internal grinding would be far better but you'd need a pretty good toolpost grinder and again lot's of experience for that as well. Myself I think going with a real good and high quality MT reamer if that female taper is soft might be the better way. For something that critical you don't find the cheapest one possible, buy a good brand name one so you know the dimensions of the reamer can be trusted 100%. Chewed up MT bores are the main reason I won't buy or use any tooling where the male MT isn't in pristine and spotless condition no matter how cheap it might be. I've been there before and don't need to revisit that issue with my equipment again. 
Re: Tail stock worn quill.
Thanks Pete, you hit the nail on the head. I thought my post was pretty clear about it being a morse taper issue, I was about to try rewording it lol. Do you have any idea about the thread you mentioned about repairing it or do I just go to the site and start looking?
Re: Tail stock worn quill.
Likely best to just run a search over on PM Joshua since I read a lot of the various sub forums there and I'm not 100% sure of exactly where it was. It was a couple of years ago when I came across that rebuild thread. Memory could be faulty, but for some reason I thought that thread might have been in the Schaublin, Cazenuve, Weiler etc lathe sub forum. But a few search terms about tailstock rebuilding should pull it up.The poster did do a great job of reboring the tailstock dead inline with the headstock to remove wear, bronze sleeving that, then line boring undersize. He then had it precision honed at I think an automotive engine rebuilders shop so there was well less than a thou of clearance. All that was done after the tailstocks quill was hard chromed and ground back to size, roundness and exactly parallel. Again it could be faulty memory but I thought he had the quills morse taper hard chromed and then had that reground as well. Like I said, a great deal of work and not exactly cheap to have that work done by a few specialist's, but he was rebuilding the lathe back to new or better condition anyway.
I had to learn the hard way to either keep the tailstocks quill capped when there's nothing in it plus be real good about making sure any tooling has the taper wiped spotless clean before inserting it or you will have future and costly problems. Even a good MT reamer is going to cost $75 - $100 just to lightly clean up any score marks. So for me it's now just easier to try and avoid the problem starting at all. Since a MT holds both by friction and a slight wedging action it doesn't take much of a burr on the bore or the tooling to lose a lot of there holding force as I'm sure you already know. Even brand new but cheap as possible offshore tooling can have the MT just slightly off and that leads to tools spinning in the bore as well. The angle tollerances for Morse Tapers are pretty specific and it sure doesn't take much error in the finish grinding before they'll only hold on a very small area. High quality cutting tools do have that high cost for multiple reasons, and most have very little to do with the cost of labor imo.
One possible thought? If you could find a common lathe with parts that are available (Grizzly?) that has the right size MT that you want and the quill is still a bit oversize to fit yours, then maybe the cheapest fix would be to order one in then just have it's O.D. reground to fit yours. Or sleeve and rebore to fit yours like that poster on PM did. The rear ACME thread in the quill could still be a problem, and maybe it's length, but they must use fairly standard sizes and thread pitches.
I had to learn the hard way to either keep the tailstocks quill capped when there's nothing in it plus be real good about making sure any tooling has the taper wiped spotless clean before inserting it or you will have future and costly problems. Even a good MT reamer is going to cost $75 - $100 just to lightly clean up any score marks. So for me it's now just easier to try and avoid the problem starting at all. Since a MT holds both by friction and a slight wedging action it doesn't take much of a burr on the bore or the tooling to lose a lot of there holding force as I'm sure you already know. Even brand new but cheap as possible offshore tooling can have the MT just slightly off and that leads to tools spinning in the bore as well. The angle tollerances for Morse Tapers are pretty specific and it sure doesn't take much error in the finish grinding before they'll only hold on a very small area. High quality cutting tools do have that high cost for multiple reasons, and most have very little to do with the cost of labor imo.
One possible thought? If you could find a common lathe with parts that are available (Grizzly?) that has the right size MT that you want and the quill is still a bit oversize to fit yours, then maybe the cheapest fix would be to order one in then just have it's O.D. reground to fit yours. Or sleeve and rebore to fit yours like that poster on PM did. The rear ACME thread in the quill could still be a problem, and maybe it's length, but they must use fairly standard sizes and thread pitches.
Re: Tail stock worn quill.
I thought the initial question was about the ram wiggling in the tailstock casting. I did like the suggestions to renew the taper.
One has to be done before the other. The plating of the ram is interesting but Read Pete above.
Well, I keep editing because a Harrison is like a Colchester and I don't see parts from a Grizzly .... we will see.
One has to be done before the other. The plating of the ram is interesting but Read Pete above.
Well, I keep editing because a Harrison is like a Colchester and I don't see parts from a Grizzly .... we will see.
Re: Tail stock worn quill.
I meant finding a new tailstock barrel from a new lathe that's available today with the MT he needs Spro. Sleeveing, boring and honeing the tailstock to fit the new quill would be the cheapest part of the operation. Even better if a quill can be found that's hardened. If and it's a big if Harrison or other than made Josh's lathe even have a new quill you can bet it's going to be very expensive. Even with that it still depends on just how much wear the tailstocks bore has right now. We used to get hydraulic rams that were lightly damaged or scored hard cromed then reground back to size. If what I was told is correct about .020" - .030" of plating is the maximum there willing to gaurantee the work for the plating standing up to working conditions. Heavily scored rams would be welded first, ground, plated and then reground to size.
Re: Tail stock worn quill.
This is good information, Pete. I was a little fudgy about that because I wanted the dimensions of his Harrison's tail ram. Some could be the same and then they changed later. I have a Clausing Colchester ram for a 15" in the box and it may be worth a pile. No way can I sell it to be modified.