internal spindle bushing material ???

H

Hal

New member
My lathe (10EE)has a loooong spindle bore 24 1/2" and 1.4 in dia I.D. .I would like to chamber through the headstock.

I've searched and read all the post I could find.

On the right end I thought I would make up D1-3 back plate chuck like Butch and a few others have posted pictures of.

The left end of the spindle is threaded.

I would machine a cap to fit the outside of the spindle, the center of the cap would have a 3/4" threaded hole in which a matching rod would pass through.


I would make up a 3/4" rod 1' long +-. One end of the rod would be threaded for about 6" to match the spindle cap and the other end would have a 60 degree center on it.

A bushing for the 3/4" rod would be made to just fit the I.D. of the spindle (-.001). the pointed center would extend past the bushing an inch or so.

The threaded rod would adjust to different length barrels.


What material would be best to make the bushing out of aluminum or a type of plastic??

Is this a workable idea or is there a better way.

Hal
 
It sounds like you are counting on the inside of the spindle at the left end having no runout. Do you know what it is?
 
I don't remember since I don't have a Monarch any more but if the inside of the spindle isn't precision all that won't be any too accurate. My South Bends are not precision inside. I must type slow. Kenny
 
Hal

I think you would be just as well off to put a set of soft jaws in a good adjustable 3 jaw, true them up, true the OD of the barrel between centers, put it in the chuck and indicate the barrel in and leave the muzzle alone. You run the risk of doing more harm than good when you depend on the ID of the spindle.

Dave
 
I'll have to check the run out.

I wrongly assumed that the inside would be true . Its a tool room lathe and from the factory it had, when new.000030 and a top RPM of 4000 RPM. (thou mine is far from new)
I thought the spindle would be ground inside and out to help balance it at high RPM.

Dave I have a 6 jaw, will that work better than a adjustable 3 jaw?
With the barrel shank trued between centers, just clamp the trued shank in the soft jaws and let the muzzle end of the barrel extend into the spindle bore and "free float" Correct?

Hal
 
Hal

Everything we are taking about is a compromise. If you go the chuck route you shouldn't need to support the muzzle as long as speeds don't get to high. If you did everything right the muzzle should be running pretty true. If you build an inboard spider you will have to support the muzzle. Joel Pendergraft's spindle insert comes to mind. It would be easy to make using my idea of ball bearings instead of pins. If anyone is interested I guess we could start another thread and get Joel involved in the discussion also.

You don't need all 6 jaws. As long as you have an adjustable chuck get 3 soft jaws. Put a ring on the inside of the jaws aproximating barrel size, put a load on the chuck, take a pass with a boring bar. This gets the jaws running true with the headstock. Then true the barrel and set up and indicate the barrel in by moving the chuck. Or see "food for thought" below.

spott3r

Gordy is a dear friend of mine but I don't agree that you have to give up one thing to get another. I have no problems with chamber concentricity while maintaining a repeatable near zero condition from barrel to barrel.





Food for thought.

For those of you who have not caught on to Gordy's trick with the long rod. It works almost like a long stem indicator. It doesn't have the same resolution as .0005" Intrepid indicator used inside the barrel but if you used a tenth indicator on the rod you could get very close.



Now, if you think a rod on the inboard side will work why can't you do it on the outboard side. Make an insert similar to what Joel Pendergraft and I were talking about. Have some long allen wrenches around and come up with a way to hold a rod on the outboard side.

This is how I learned when I first got started. I was a gleaner. I picked up bits and pieces from a lot of good smiths. Adapted those ideas and developed some of my own over the years. I'm still a gleaner.

Dave
 
Jackie schmidt used to chamber on his 10EE. He made a post some time ago about how he did it and what he used and made for tooling for chambering on the 10EE.
 
Thanks Bill De I'll do a search. I thought Jackie S. also uses a pilot center bushing on his Pratt & Whitney now.

Hal
 
Butch Lambert said:
You are right Hal about Jackie. I will trade you my 6913 Clausing for your 10EE.
Butch
Click to expand...

Butch,

I bet you would!

Hal,

Would you be able to get a barrel between centers as Mr. Tooley suggests? Most 10EE are what...about 20" between centers? Unless of course you have a rare long bed 10EE. If so, I will trade you my lathe, wife, and a couple of dogs for it.

Justin
 
Spindle OD

Gentlemen,

If one is a little twitchy about using a barrel centering mechanism that depends on the spindle ID, why not use something that is based off of the spindle OD? The OD should be ground, and have minimal run out, should it not?

Justin
 
Hal, I serched for the post by JS and did not find it. You should send him a message and ask. I do barrel work on my 10EE, send me an email to anne_bill5(at)msn.com....
 
jlcprec said:
It sounds like you are counting on the inside of the spindle at the left end having no runout. Do you know what it is?
Click to expand...
I'm having a problem here. Everyone is suddenly jumping on the bandwagon of chambering by lining up with a long rod and letting the muzzle flop to wherever. Sometimes as much as 0.075" from one eye witness who saw the demo at the SHOT Show.

Now there is popping up a concern that the bore in a lathe spindle may be out a few thousants. This could be, but Ill bet the farm that a Monarch EE will not have spindle bore runout to an amount of over 0.002". Monarch is going to sell an $85,000 lathe that the spindle bearings will run within 0.00003" at 4000 rpm, yet has significant runout in the bore?? I don't think so!!

Nothing personal jlcprec, but I bought, had rebuilt, and witnessed too many acceptance tests of Monarch EE's at Monarch/Sidney to be concerned about spindle runout in the spindle bore.

I just checked, my old 1944 South Bend Heavy 10 has less than 0.003" at the tail end of the spindle bore.
 
Butch Thanks but I probably couldn't afford the freight from TX. - MT.

Zebra It is a 30" EE, Also thanks but I already have a lovely wife (she is reading this over my shoulder) and a dog. I try to keep mad women and gun separate :) it's good for your health.

Bill De I did a search also and nothing turned up. I'll send an email.


Hal
 
Dave Tooley..

I absolutely defer to your experience, Sir.

I just hope to be as good as you one day.

I recall reading that the inside of the spindle is not a nicely machined place since there was little reason to by the manufacturers.

Have fun,

Spot
John M. Paton
 
John

Don't defer to my experience. I'm still learning new tricks all the time. I may not apply them today but someday they may make it easier to do a good job on some project. Keep your eyes and ears open.

Hal

It's not a matter of how nice the spindle is machined. Nice means pretty to me. It how concentric it is. Then that idea goes out the window when you compare the ID of a barrel with the OD of the barrel. So a concentric spindle bore really means nothing. It's about developing a process/system/tooling that has a range of adjustment to adapt to any barrel configuration and the creativity to use it. Reminds me of a Clint Eastwood movie about a Marine gunny sergeant "adapt and improvise".

For all you guys who can't afford a Monarch look around for a Nardini 10X30 or a 12X30. For what we do I would put it up against everything but a Monarch.

Dave
 
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