Anyone using a spring pole lathe?

[Bob Glenn]

I've recently built a spring pole lathe, using Roy Underhill's pole lathe as a starting point. This weekend I am going to use it to turn chair legs at an eighteenth century re-enactment. ( see Grandpa would be proud, In Neandrathal)

Now the problem. The lathe works well, however, I am having trouble getting my chisels to cut. I mounted a fresh piece of green maple and rounded it with a roughing gouge with some success. However, when I put my parting tool to the work to layout the minimun and maximum diameters, it left a frayed edge on both sides of the cut. Next I experimented with my skew and had very little luck, and what cutting it did do, was unsatisfactory. The skew left a little better finish the next days after the wood dried a little.

A couple of my gouges, like my finger nail gouge wouldn't even cut unless I raised the handle to a point where they were scraping. It seems like if there is low angle grind on the bevel, the gouges don't want to cut.

Right now, I don't think there is anyway I could turn a double baluster leg on the pole lathe. It ususally just takes me about twenty minutes to go from log to a finished leg on my powered lathe.

Any suggestions here? I know the old Bodgers working in forests could turn out an amazing amount of legs on a pole lathe. My chisels are reasonably sharp. One big difference I've noted is slower turning speed. I usuall turn spindles a 1000 RPM, and I'm sure I'm not even approaching that. Also I'm getting about two revolutions per cycle of the treadle.

Any help would be appreciated. I'm not a schooled turner, but learned by gosh and by golly.:confused:

Bob

[Don Orr]

It sounds like you know your way around a lathe so I doubt sharpening is an issue. Wet wood does tear and fray quite a bit against a parting tool, maybe make a cut line with the point of a skew to help reduce it. I've turned on Roy's portable pole lathe at a demo and it worked pretty well. Silly question- is the drive rope wrapped the correct way around the workpiece? Wish I could be more help.

[John Taylor]

HI

I have done a bit of bodging in the past and the one thing I do remember is that the tools and the way you use them are different to the usual tools we use nowadays on electric lathes.

A good site to visit is http://www.bodgers.org.uk which has a lot of info, they also have an ask and answer section which should have all the info you need.

john

[Bob Glenn]

Don, thanks for skew idea, I think I'll give that a try tonight. Yes, the rope is wrapped in the right direction. I was looking at the Bodger's website. There lots of pictures of spring pole lathes. I may try to lengthen my treadle from three feet to about four feet long. This may give me more RPM and more revolutions per cycle. I also remembered my tool rest is still a bit too high, so I plan on lowering it a bit tonight also.

Ray has always said, using a foot powered lathe will teach you to correctly position your tools on work so they cut rather than scrape. I may be in for some studied work, applying the edge to the turning wood. :rolleyes:

Believe me this little spring pole arrangement has me really appreciating my powered lathe! It reminds me a little of turning my first double baluster leg for a Windsor chair. It took me about five tries until I got one that I liked. Then all I had to do was make three more just like it! :eek: Much harder!

[Bob Glenn]

Thanks, John, I'm getting much more familiar with the Bodger site.

[Bob Glenn]

They said on Bodger website not to try using tools ground for a pole lathe on a high speed lathe. They didn't say what the difference in the grind angle is. Anyone care to speculate? Right now I'm just experimenting trying to find what works.

[Jim Underwood]

I wonder if you used carbon steel tools rather than HSS whether it would make a difference? I've noted several turners say that CS will get sharper if not hold an edge as long.

Perhaps a steeper angle would help?

For the parting tool I wonder also if you had a concave surface on the cutting edge if it would score the edges of the cut and help prevent the fraying? Some parting tools are meant to be sharpened in this manner.

Just some stray thoughts.... Hope you figure it out. Let us know what you come up with. I'll finish my treadle lathe one of these days, and this info may come in handy.

[Bob Glenn]

Right now my thinking is a shorter bevel is what is used on chisels for a pole lathe. It would make sense that trying to use a chisel ground with a short bevel at higher speeds, would make for lots of catches and snags.

Got to thinking about RPM last night. At about one leg pump per second, and two revolutions per pump, thats 120 RPM.....not very fast! With a longer treadle, I may be able to get three revolutions per treadle cycle and take the RPM's up to a whopping 180!

Thanks for the thoughts. I'll let you know what I find out.

[John Schreiber]

You mention that you are getting only two revolutions per stoke. I think the spring-pole lathes I've seen get a lot more than that. If the end of the pole is moving three or four feet per stroke and the diameter where it is wrapped around the work piece or the lathe head is two inches, you should be getting five-to-seven revolutions per stroke.

I don't know much about spring pole lathes except that I've always wanted to try one, but I hope that helps.

[Bob Glenn]

John, you make a good point. The spring pole lathe I have built has the pole incorporated into the lathe itself. It is like the one Roy Underhill occassionally uses. There are two poles that run under the lathe bed bewteen the uprights. They are tied together in the middle and one end of the top pole is allowed to flex up and down inside a long mortice. A rope secures that end to a cross piece that sits on top of a fulcrum support and transfers the up and down motion to the work below on the other side of the lathe. (confusing isn't it?)

I'm only getting about three feet of travel on the drive cord. Still on a three inch diameter turning, which is about what I start with, I should be getting around four revolutions.

Oh well, I'm just going to have to keep experimenting with this thing. I better hurry, as I'll be demonstrating with it this Memorial Day weekend. :eek:

[Doug M Jones]

Bob,
Please post some pictures of the demo. I'd love to see your lathe.

[Chas Jones]

Bob, I was watching a pole lathe worker on Sunday and was amazed at the finish he was getting on some green ash with what I presumed was a skew, having a closer look and a chat with the guy I found it was just a 2" wide wood chisel ground with a very shallow angle (20deg or less) flat bevel, looked more like a knife edge than a regular chisel.

He said sharpness was the key to good finish, (isn't it always) it was used bevel rubbing.

The nearest to depth markers I saw him do were done with a narrower skew on edge, cutting a vee on alternate sides much like starting to form a bead.

[Bob Glenn]

Well, I assembled the pole lathe last night for a last go before the re-enactment this weekend. The design, lets me knock down the lathe to haul in my van. Takes about five minutes to set up and goes together with wedges, no nails or iron screws.

I played around with the tension on the poles a bit and I am now getting more revolutions per stroke, about three or four. I've reground my tools with a shorter bevel and that seems to work better.

This is like learning to turn all over again. I found out last night, faster is better! :rolleyes: Duh, go figure. I got a smaller parting tool, that does an adequate job with out tearing out the wood.

So here is what I am beginning to learn you have to do to operate a pole lathe:

!. You have to balance on one foot, while you are pumping up and down with the other foot.

2. Because you are pumping the treadle, the whole lathe is going to move around some what.

3. When you put the lathe tool to the wood, if you don't have the angle and pressure just right, the piece will catch and stop turning.

4. Since it only cuts on the down stroke, you must ease off on the pressure on the return stroke. Ease off too much and you will have a hard time putting the tool back on the piece in the same place during the next stroke. (for the life of me I couldn't roll a bead last night)

5. All of the above works only if you have the lathe set up just right. The treadle must be positioned correctly or the drive cord will be off the end or over where you are turning.

Thanks for all the suggestions. I'll try to get some pictures then try to figure out how to post them here.

Bob

[Larry Gelder]

Well, I assembled the pole lathe last night for a last go before the re-enactment this weekend. The design, lets me knock down the lathe to haul in my van. Takes about five minutes to set up and goes together with wedges, no nails or iron screws.

I played around with the tension on the poles a bit and I am now getting more revolutions per stroke, about three or four. I've reground my tools with a shorter bevel and that seems to work better.

This is like learning to turn all over again. I found out last night, faster is better! :rolleyes: Duh, go figure. I got a smaller parting tool, that does an adequate job with out tearing out the wood.

So here is what I am beginning to learn you have to do to operate a pole lathe:

!. You have to balance on one foot, while you are pumping up and down with the other foot.

2. Because you are pumping the treadle, the whole lathe is going to move around some what.

3. When you put the lathe tool to the wood, if you don't have the angle and pressure just right, the piece will catch and stop turning.

4. Since it only cuts on the down stroke, you must ease off on the pressure on the return stroke. Ease off too much and you will have a hard time putting the tool back on the piece in the same place during the next stroke. (for the life of me I couldn't roll a bead last night)

5. All of the above works only if you have the lathe set up just right. The treadle must be positioned correctly or the drive cord will be off the end or over where you are turning.

Thanks for all the suggestions. I'll try to get some pictures then try to figure out how to post them here.

Bob

Bob,

I'm not a turner yet, but want to soon build a SP Lathe. Now that you have a few months behind you, would you please update us about your progress?