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PM3520 Converted to Gap Bed Lathe

Jerry Hall

Jerry Hall

Joined
May 7, 2004
Messages
315
Likes
1
Location
Lincoln Hills, CA (At the foot of the Sierra Nevad
Website
jerryhallstudio.com
Well not exactly. But I am on the track. I have been looking at all the various shop made and purchased solutions for outboard turning. Also seriously considering a Stubby and didn't want to buy or build any attachments for the 3520, or increase its length with a bed extension in my space challenged shop. As I was leaning my butt against the nearby Delta 460 teaching lathe a thought slowly moved up from my posterior to my frontal lobe. The Delta is on wheels, and the spindle was about the same height as the 3520. Hmm.

So I had this piece of out of balance redwood driftwood. I wanted to turn a wildly off-center bowl into it and had mounted on a faceplate fixture with counter balancing. but the 25" swing was to much for the 3520a. (I know, just get the Stubby!)

Well as you can see in the picture I wheeled up the Delta, moved the 3520 headstock to the end, swung my 3520 tailstock out of the way, adjusted the Delta tool rest, and said to myself this will never work. But it seems to anyway! I don't think it is a joke. By better siting the delta on its bench to give more reach for the banjo and clearing out some interference for 32" bowls I think it is practical! Pretty sturdy while turning even tho the cabinet is still resting on wheels.

I think it is feasible to make up a special purpose banjo that can hold my 1" dia post tool rests from the 3520. Now I have to figure out a way to rotate the Delta Tail Stock 90 degrees so I can turn between centers....The ideas just keep on coming.

I don't turn these things every day, but it is a fast setup and may open up a lot of possibilities.

But I still want the Stubby.
 

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Hi Jerry, I'd love to see more pictures of the attachment.

I've never done an outboard turning. With this said, I've thousands of questions (if I can remember them all lol.)

Just curious to know if it's also important to have 2 bearings on the outboard side of the lathe---given than there are usually 2 bearings on the inboard side of the lathe.

Thanks
 
My only suggestion would be to fasten the Delta to the Powermatic somehow. I have done this with a Nova comet and Nova 3000 to get a longer bed, not a gap bed. It worked well.
I have both of those lathes and may give that try for a project I'm working on right now. I have the 3520A but I plan to drill the leg for the 18" bed extension that I have so I can lower it like the 3520 B does.
I'm thinking I might store it under the lathe for most of the year and when I need it I can either bolt in on the bed or bolt it on the lathe.
 
Instead of trying to figure out how to rotate the Delta tailstock 90°, take the easy route and rotate it 180° and then joint the two lathes tail to tail. Don't try it with the two lathes not solidly connected together or else you won't be able to get anything that is out of balance trued up.

One of our club members has bolted two PM3520 lathes end-to-end in order to turn some large architectural pieces.

The simplest solution is to get one or two bed extensions if you need a longer bed.

A simpler solution than trying to get the Delta midi to work with a larger toolrest is to simply make a freestanding toolrest
 
Jake, John

John and Jake, This was sort of a joke that turned out surprisingly well.

Jake, I really don't know anything about the bearings. Surely that would be a factor with ginourmous blanks. I have heard of some starting out with hundreds of pounds and working it down to a couple dozen pounds. You will need a tolerant housemate and a big table to display such a thing!

My setup was all done in about 5 minutes, just rolled up my Delta to just clear the driftwood, removed the tailstock. Positioned the wimpy Delta banjo and rest, hand rotated to be sure all clear and turned with the gouge directly above the post. Any farther over the rest and I am sure things would have gone badly. What you see in the picture is what you get. All the other messy junk in the picture is unrelated tool holding fixtures and a tailstock swing-away for the 3520. If you are interested I will post a picture of how I mounted the driftwood to a 2x6 backing board with hot glue and wedges here and there. Then a faceplate on the back of the board. I may turn 2 or 3 bowls in the driftwood, relocating the face plate and rebalancing with bolts and such. The hot glue peals off ok with minimum damage to the surface.

John, Tying things together is a wise idea, especially for heavier out of round blanks and if I gin up some way to use a tailstock. Mounting your 3520 extension as needed would be nice. Maybe with hanger slots milled out for the bolts like the Robust Sweet 16. Stowing it away under your 3520, or maybe on hanger bolts waist high on a wall so it is easy to get at and lift. It could even be on a reverse L shaped cart that would match up nicely with the bolts. It's all an experiment!
 
Barry: Re necessity the mother of invention

Point well taken, but it occurs to me that for us turners and given our tool fetish that "invention is the mother of necessity."

No sooner does a new gadget come out then we all seem to need it.

Jerry
 
Hal re "other stuff"

Attached is an annotated picture.

- The tailstock swingaway is very handy and easy to build as shown in this slide show:
http://picasaweb.google.com/jerhall95945/SwingAwayAndDownTailstockForPM3520
- I mount my dust collector cone to the dowel - it is an old sheet metal light shade.
- The MDF washers are turned from 1/4" mdf with a 1-1/4 inch hole slipped over the spindle of PM3520 to avoid the chuck locking up and to insure that it can be removed without a hassle.
- The tool shelf is also fastened on the other side by an angled leg attached at the headstock where the release lever attaches to the head stock. A little Rube Goldberg but it is very handy. I have to clamp the shelf down when turning large heavy wet blanks tho as it bounces around to much. But it is worth it to have the little fixtures handy and my hone and current tools at hand. I also turned a long handle to extend the headstock release lever. Easier to reach and more leverage to lock it down.

Hope this does it. Let me know if you want a better pic of the shelf.

Jerry
 

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Bill: re Tail Stock Swing Away

Bill,

I have thought of a more refined hinge which would take the slop out the movement. In truth this was a mockup that I was going to have redone by a welder friend after I tested it for a while. But the darn thing just keeps on working, six years now with no signs of wear and tear.

If I were to replace it I would copy this one:
http://www.jtturningtools.com/tailstockmanager
and without a worry since my design was "prior art" 😀
But really I would just buy his. It seems well executed.

But now I have a Stubby on order and am going to let go of my much loved and used and abused Mustard. When I repaint it and the fixture I will just label it as a brand new model: PM3520C.

And I still do not want to discuss the extra holes. It hurts every time I look at them.

Jerry
 
The reason that I thought of commercial door hinge is that I have a lathe project where the motor is hinged to tension the belt. My project is not as old as yours, but not too far behind. However, mine still has not been completed.
 
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