Removing Drive Center

[bca13]

I am hoping for some help on getting my drive center out. I have a Powermatic lathe and when I put the bar in to push out the live center on the tailstock the front part of it broke off from the portion that goes into the tailstock. The problem is that the bar does not hit the edges of the tapered part.

Any ideas? I am thinking of trying to epoxy the front part on. Will the epoxy hold enough to pull the tapered part out with it?

Thanks...

Ben

 

[dkulze]

That's not good, Ben. I'm not familiar with drive centers that are hollow as you describe yours. Seems like a poor design for exactly the reason you state. Your best bet is to use a larger tap out rod. Pick up a steel rod from the nearest Home Despot that is a close fit for your drive spindle. This should give you the contact you need to drive the center out.

If that doesn't work, tapping the center and putting in a bolt would probably do it. You could drive it right out then.

I don't think epoxy would do it if the original structural metal would not.

Good luck,
Dietrich

 

[Dario]

Ben,

Not sure I understand it properly but if I did...I believe you just retract the tailstock by cranking the tailstock wheel and the live center should pop out.

 

[MichaelMouse]

Mixed message. Tailstock, you have a hollow type live center with removeable tips held by a #0 morse? Larger bar is the answer. Believe 3/8 is the standard, with 5/16 to remove the tip taper.

In any case, if you have anything left up front besides the taper, put a piece of wood between it and the front of your tailstock casting and retract. Should pop right out. Used the method all the time on my old Delta when I got a NOVA live center with hollow shaft.

If you had threads and snapped them off, it's possible you can thread a bolt or nut in or on and pull while rotating. Not important if they're cross-threaded if they're already damaged.

 

[Bill Boehme]

Are you having problems getting the drive center out or is it the live center? If it is the live center, you just crank the tailstock to the fully retracted position and the live center will pop out. I think that the brass tip on the knock-out rod screws into the end of the steel rod -- if so, you will need to get a replacement tip. Epoxy will not work because it does not bond well enough to the metal to hold up to the shock loads. The proper way to use the rod on the drive center is NOT pushing the drive center out, but giving it a very fast and sharp rap. Little taps are not the way to do it either as each tap that does not remove the drive center just puts all of the impact energy into the ball bearings.

Bill

 

[dkulze]

Actually, if it's the tail center, cranking it back may not work. A fair number don't have this feature (my jet does and my nova doesn't). If you have threads or can cut threads, all you have to do is run in a bolt then knock it out as normal. The bolt will fill the hole quite nicely for this. No pulling required.

Bigger knockout bar is the best answer, though.

Dietrich

 

[john lucas]

Ben With the powermatic you should be able to crank the tailstock all the way back and this will automatically eject the live center. However if for some reason the live center is too short try placeing a piece of metal between the tailstock housing and the rear flange of the live center. You need to have the quill extended slightly. Then crank the quill in and the metal will act as a wedge and pop the live center out.
I have a Nova live center. It is hollow and can't be knocked out with a knock out bar. probably the same problem your having. The knock out bar simply pushes the front center point out. The front center point is a short #2 morse taper so I just push it back in. On the Powermatic I can simply eject it by cranking the tailstock quill in. On My Nova lathe I use a skew as my piece of metal to go between the tailstock and live center and then crank the quill back and pop it out.
I hope that answers your question.

 

[Ken Grunke]

I'm pretty confused by Ben's post, I think he needs to clarify this further. You say you need help getting your drive center out, which I take refers to the headstock morse taper. Then you mention tailstock, and it's not clear whether you mean the taper for the tailstock ram, which commonly is a #2 morse taper for the main shank, or the interchangeable points on a live center which could be one of many different types of standard (or non-standard) tapers. Like Mr. Mouse says, mixed message!

 

[bca13]

I got it...

Thanks for all the people that responded. What was happening just to clarify. I put the livecenter from my midi Jet VS in the tailstock of my powermatic. When I put the knock out bar in and hit it just the part that spins came off and the morse taper part stayed in. The inside of it was just large enough that the knock out bar slid right through so I could not angle it. Normally I can just crank it back and it pops out, but this one was too small. Dario called and when we were talking about it the light bulb went on. I cranked the tailstock so it was completely extended and then pulled it out. At this point it was really easy to knock it out. I did not know that you could remove that part of the tailstock. All is good now.

Thanks,

 

[Bill Boehme]

As you have discovered, the center point is tapered and it will fit snugly back in place if you give it a good rap with a block of wood -- no need to glue it -- and there may be occasions when you will want to remove the center point.

Bill

 

[Martin Braun]

Ben - I'm curious. Why did you take the PM live center out & put the live center from your mini in? Are you working on something that required more clearance at the tail stock?