A Bowl on a Pole Lathe

[Darrell]

Hi all,

Well, I managed to obtain some small success in my second bowl turning attempt. The first try was one of those 'learning experiences" one hears about. One learns from one's mistakes, eh?

Ed in Oakville dropped off a chunk of recently cut maple for me to practice on, and I roughed out a couple of bowl blanks from this rapidly drying maple, slathered them with wax emulsion, and put them in a plastic bag to keep them wet enough to work. Time passed, my summer holidays approached, and the bowl blanks grew mouldiy and ugly.

When I finally got to the cottage (where my pole lathe lives) the weather was not conducive to spending a lot of time outside at an activity like operating a pole lathe. Sitting on the beach drinking cold beverages was a more proper occupation when the temp ran over 35 C. So I set up the lathe in the "basement" (more correctly termed a crawspace in this instance, but tall enough for a short guy like me) and mounted the Bodger's Muddle in the rafters above. The basement was a bit cooler than the Great Outdoors, so I could actually work on the lathe without expiring from heat exhaustion.

I used the mandrel I made in July (scavenged birch from the firewood pile). A 1 inch hole bored in the face of the bowl blank would accept the end of the mandrel. Note the interesting "stuff" growing on my bowl blank...



I rounded the outside of the bowl first, using a roughing gouge and a Sorby bowl gouge. I dunno if the Old Guys used anything like a bowl gouge, but it worked great on the pole lathe for me. Now that the outside was round, it was time to start hollowing.

And here's the fun part: you can't get too close to the centre because you need the strength there to drive the bowl, and if it gets too thin, then that hammered-in tenon will split that mortice. That's one of those "lessons" I mentioned earlier.. Now the really funky tools come out to play. Apparently I needed a hook tool.

Not being totally useless in the shop, I had made my own hook tool. I used a piece of a tine from an old horse drawn hayrake, a forge made from a frying pan, and a bit of scavenged 2X2 to make my hook tool. These things are apparently supposed to be used on the bottom of the turning, on the surface moving away from the turner. Kind of on the pull stroke. I started out turning the blank by hand and holding the tool in various orientations to try and get a feel for what angle and direction I needed to use to make this weird thing work.



A few tentative attempts were required before I gained the confidence and learned the appropriate technique to get shavings to flying. And fly they did! It was then a matter of working my way down to the bottom of the bowl. I can't say much about the smoothness of the surface, but that's likely a technique problem. Or perhaps a sharpening issue? There are a lot of ridges in the surface, but no tearout. Hmmm, maybe I need a selection of various shapes and sizes of hook tools? More tools? Of course!



Now what do I do about the core? I can't work any closer to the centre with my hook tool. That Sorby bowl gouge to the rescue again! I kept working the core down until I finally intersected the mortice and the bowl flew off the lathe. I managed to catch it before it hit the floor (reflexes still OK so far...). So now I have some cleanup to do on the inside, and a bit of sawing to get the base off.



The base makes a handy way to hold the bowl in a vise whilst working on the last bit of the core. I attacked the inside of the bowl with a chisel and a hook knife and very shortly the bottom was smoother than the rest of the turning. Then I sawed off the waste from the bottom.

And it's a bowl!. I packed it in a bag of fresh shavings to slow the drying process, and that's where it sits now, waiting for the first crack to develop...



Bah. I had to delete half my pix from this post 'cause the Forum software limits you to FIVE images. You get the idea anyways...

Darrell

[J.P. Rap]

HOLY SMOKES! Those are some impressive shavings from a pole lathe!

I hope you packed it in a paper bag and not plastic. Keep an eye on it and change the shavings once in a while or it's going to go moldy on you again.
But you already new that didn'tcha.
I susspect a lot of the roughness is because it's green. Once its dry a round cabinet scraper sould make quick work of those high spots.

Great job. I always enjoy seeing stuff that comes off that lathe.
J.P.

[Bill Simpson]

I am impressed, A non turner would not even consider the practice of a pole lathe. and a Bowl to boot. Hats off to you for the effort.

Of course that isn't a Oneway with chuck so you are really practicing , right?

(My tounge is deep within my cheek) (Tung Oiled cheek)

A true turner you are and I am glad to have seen the results. Thanks for the post.

[Ed in Leaside]

Hey Darrell

Bah. I had to delete half my pix from this post 'cause the Forum software limits you to FIVE images. You get the idea anyways...

Not to worry. I followed the crumbs over to GIC and saw the rest of the pics there. ;) Any reason for not breaking it into 2 posts?

It looks like you had a lot of fun doing that bowl regardless of the weather. You mentioned having some problems with ridges (or were they ripples)

I can't say much about the smoothness of the surface, but that's likely a technique problem. Or perhaps a sharpening issue? There are a lot of ridges in the surface, but no tearout. Hmmm, maybe I need a selection of various shapes and sizes of hook tools? More tools? Of course!

More tools is always good but I wonder if cutting a second, smaller section on the mandrel (2nd gear) to use after you've removed most of the innards might help. Note that that's a WAG as I've never turned on a pole lathe. When I get harmonic vibration induced ripples changing the RPM sometimes helps. Then there's also that long overhang from the rest ...

Ed

BTW, how'd the bedposts go on "stretch"? My GI stretch to 104" C-C is almost ready.

[Darrell]

Hi Ed,

You asked

Any reason for not breaking it into 2 posts?

'cause I'm too lazy?

The ridges were not harmonic ripples. I think it is due to the width of the hook tool. Once the curve gets tight enough, the cutting and trailing edges of the tool are both touching the work at an angle that allows the trailing edge to dig in a bit. Thus the impetus for a smaller tool. I asked around on the APT website and was told that my hook tool was rather large, 5mm diameter is typical for the hook. Then again, they also said that the ridges were common on ordinary woodenware way back when, and only the really fancy stuff was smooth.

I did think of a stepped mandrel, but as I have so very little experience with the process, I didn't know what would work best.

PS No bed posts yet... still waiting on SWMBO to complete the design.

Darrell

[Gene45]

So how do I get to see the pictures?

I may be slow, but I can't find them!

[Darrell]

I can't find an Edit button on my post, so you'll have to look in my gallery.

There is going to be a gathering of Pole Lathe enthusiasts (well, maybe 'enthusiasts' isn't quite the proper word, but you get the idea...) on July 5th up near Cobden ON. Terry from Ottawa is organizing the event. I'll be there with my lathe & shaving horse.

Darrell

[Bill MacDonald]

I've edited your original post and added the pics from your gallery. Good thing they had the same names in both spots! Anyway, now folks can see your nice work again.

[Pete in Welland]

I am really interested in a pole lathe. I have looked at all the stuff on the internet and read your post several times. I notice that you used a mortice to mount the blank and Robin Wood uses a 2 pronged mandrel between centres. Any reason why?
Also I am getting on in years and not the healthy young stud I used to be so my big question is just how physical is it? You mention the heat factor so I assume it is a pretty good work out. Can you do the bowl in one go or do you need long breaks?
The reason I'm asking is I want to build one but if I can't physically use it then there's not much point.

[Darrell]

I notice that you used a mortice to mount the blank and Robin Wood uses a 2 pronged mandrel between centres. Any reason why?

Robin's mandrels are intended to be more-or-less permanent fixtures. He expects to make a LOT of bowls using those mandrels. Notice that some of them have iron hoops to keep them from splitting. My efforts were just an experiment to see if I could do it. I have seen mandrels like mine somewhere before (online or in books, maybe in the Bodger's Gazette) and it looked simpler, so that's what I used.

Also I am getting on in years and not the healthy young stud I used to be so my big question is just how physical is it? Can you do the bowl in one go or do you need long breaks?

In 90 degree weather with high humidity ANY physical activity will wear you down. When I'm using the lathe it isn't my power leg that gets tired, it's the one I'm standing on. So I switch once in a while. I'd say it's no more effort than riding a bike. As far as making a bowl in one go, well, that's a matter of tools and technique. From what I've learned, you need to have a selection of hook tools, and practice enough to know which ones work best in different situations. I have neither of those yet, so my bowls take 3 or 4 sessions, an hour or so apiece. "Bowls", heh heh, yes I guess it's plural as I've made TWO bowls, but that's not nearly enough experience to be good at it.

As far as making a lathe and then being unable to use it, I wouldn't worry too much about that. A pole lathe is not a precision instrument, and doesn't take a lot of time or material to build.

Darrell

[Pete in Welland]

I guess it's time to pull out the salvaged lumber and iron bits and pieces I've been collecting this past decade or so and put something together. I could use the exercise