PDA

View Full Version : Older 3520 without self ejecting live center



Vilas Schroeder
04-27-2011, 10:35 PM
I guess I have an original Powermatic 3520 that was manufactured in McMinnville, TN. Being new to turning I took a class and we had the 3520B to learn on and the live center self ejects when the quill is returned all the way back. Looking at my 3520 the tailstock does not self eject the live center, the shaft that attaches to the adjustment wheel is solid so you cannot even use a rod to tap the taper out. Nothing in the manual regarding instruction for removal on the live center. What is the recommended procedure?

James Combs
04-27-2011, 10:48 PM
I don't have any specific suggestions but if you post a photo of the live center tail stock interface area it would help use make better suggestions.

If it is anything like mine I would think you could use a "forked" wedge to pry it out. Alternately you could lightly tap a tapered chisel at the top interface then the bottom then repeat until it pops free. Once it was free I think I would have the tail-stock shaft through drilled so I could use a rod.

Ken Fitzgerald
04-27-2011, 10:54 PM
Vilas,

Could something like a ball joint separator work? http://www.balljointseparator.com/ See the fork looking tool?

James Combs
04-27-2011, 11:05 PM
Vilas,

Could something like a ball joint separator work? http://www.balljointseparator.com/ See the fork looking tool?

Excellent Ken, exactly what I had in mind with "forked" wedge comment. That should do the trick.

Reed Gray
04-28-2011, 1:23 AM
Some times it is the live center, some are longer, and some are shorter. I have a router wrench that will slip over the live center, and put a small block of wood between the tailstock (cast iron part), and the wrench, then back the handle up, and it will usually pop out. The pickle forks should work as well if you want a specialized tool. When you get it out, compare it so some other live centers, or maybe weld a stub on the end.

robo hippy

Philip Duffy
04-28-2011, 4:56 AM
I have the same original 3520 and the right answer is posted by robo hippy, as usual. Phil

Dale Miner
04-28-2011, 7:12 AM
I have a live center that is about 1/4" shorter than it needs to be to self eject from any of the lathes I own. The method I used to remove it the first time or two was to wind the quill completely out of the tailstock, and put a rod in the backside of the quill and drive the center out that way. The short center also has a thru hole in the taper so getting a rod the right size to clear the inside diameter of the threads of the quill, but not go into the thru hole of the center took a bit of looking around. Now when I use that center, I put a short 5/16" bolt in the thru hole with the head of the bolt towards the handwheel of the tailstock. That adds enough length to the center that it will self eject. I did try prying the center out of the quill, but intstead of removing the center, the outer part of the center was pulled off the center arbor.

Vilas Schroeder
04-28-2011, 7:25 AM
Thanks for all your suggestions, maybe the live center is not the original. I bought this used from the owner's widow and there are two live centers and I maybe just happened to pick the short one. I did try putting a block between the casting and the bearing, but the bearing moved on the taper. May have to remove the bearing, clean everything and apply fresh bearing set.

Vilas Schroeder
04-28-2011, 8:58 AM
This used lathe had two live centers, one taper was 1/2" shorter than the other, of course I grabbed the shorter one. I got too focused on the non-ejecting that I overlooked the basics and didn't check the other live center. I tried the longer one this morning and everything works just fine. Thanks to all that replied.

David DeCristoforo
04-28-2011, 1:35 PM
Here's how I get mine off. With a flat steel bar (I use a scraper or a skew chisel) placed like this...
193031
...retract the tailstock and the center will pop right out.