How I turn away the bottom of a Hollow Form.......

[Stu in Tokyo]

OK, this is how I did it this time round, I've done this with a donut chuck as well, but this time, the hollow form was real thin like, so compressing it in the Donut chuck was not going to happen. I hope to get my Vacuum pump soon, then I'll be able to vacuum chuck it but, until then this is what I did.

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I had a square piece of wood, that I'll eventually use for making a handle on something, but today, it worked as an extended "Jam Chuck".
I turned it down so it will fit into the hollow form, and put a small radius on the end of it, so it was not too flat.

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Next I cut a round foam pad and stuck it on the end of the piece. (using the tail stock to hold the piece while the glue dries).

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I then slip the hollow form over the jamb chuck and........

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.....bring up the tail stock.

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I carefully cut the tenon away, and then sand, and finish it (at this point only sanding sealer).

With only a little stub left, I cut that off with a sharp chisel, and then sand the bottom...........

Cont.........

[Stu in Tokyo]

...........


here is the nearly finished piece....

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Six inches wide by about three inches tall, turned to about 1/6" most of the body, with the very bottom only turned to about 1/4". I've found the extra mass at the base makes these hollow forms sit better.
The wood is Red Keyaki and this is the only hollow form I've done without a collar of some sort. :yeah:

The piece is sanded and finished inside too.

The outside is sanded through #600, and finished with two coats of sanding sealer, I'll be rattle can lacquering this piece later.

Well that is how I do it, if you can help me refine my technique or have something else to add, please do. If you have a question, I'll try to answer.

Cheers!

[TTIT]

...........Well that is how I do it, if you can help me refine my technique or have something else to add, please do........Much the same as I would do it Stu except I wouldn't worry about gluing the pad on - I just slip a piece of anti-slip matting between the form and the chuck - don't like waiting for glue to dry :shrug:

[joe greiner]

Excellent technique, Stu. I'd guess the shaft is only slightly smaller than the opening?

For something this shape, and very thin walls, might even work better than a vacuum chuck. The outside air pressure would produce a similar force as the donut, just less concentrated.

Joe

[hughie]

Stu,I am with TTIT . The anti slip has worked for very well for me also. But then as you get the vac pump up and running it would do even better.But irrespective of the method, a very pleasing result. Theres an appeal of the simple clean form, not always easy to achieve. Well done!

[Hardenfast]

Excellent work Stu, and great WIP tutorial - many thanks. This is all new territory for me, and I'm still a little confused on a couple of points. If you would be so good as to enlighten an unlightened one:

What is the actual drive connection from the "jam chuck" to the vessel? Is it just the friction of the foam pad on the end of the inserted timber against the bottom of the hollow form? I see that Mr TTIT & Hughie recommend just using anti-slip matting. Either method wouldn't seem to give much holding power, as I imagine that just the inertia of starting the piece up would almost cause this connection to spin, much like a clutch?
I assume that you sand it through the different grits while still spinning, and then touch up the little tenon stub on completion? Sorry, just re-read your sequence & that bit is now obvious. What do you use as a sanding sealer?Finished to 1/16" - Holey Moley! This must be almost translucent! Have you seen examples from the guy whose work actually lets some light through the timber? Can't recall his name.

Wayne

[Cliff Rogers]

:2tsup:

[wheelinround]

:2tsup::2tsup: Stu-pendous

[Stu in Tokyo]

Excellent work Stu, and great WIP tutorial - many thanks. This is all new territory for me, and I'm still a little confused on a couple of points. If you would be so good as to enlighten an unlightened one:
What is the actual drive connection from the "jam chuck" to the vessel? Is it just the friction of the foam pad on the end of the inserted timber against the bottom of the hollow form? I see that Mr TTIT & Hughie recommend just using anti-slip matting. Either method wouldn't seem to give much holding power, as I imagine that just the inertia of starting the piece up would almost cause this connection to spin, much like a clutch?
When you put the piece between the jam chuck and the tailstock, there is a LOT of friction generated on the inside of the bowl, certainly the drive is not as good as a tenon held in a chuck, but I'm not hollowing out a bowl either, I'm just turning off the tenon. The anti-slip stuff sound great, I'll have to get some, but the foam pad works well too, even though I had to wait a few minutes for the contact cement to dry.
I assume that you sand it through the different grits while still spinning, and then touch up the little tenon stub on completion? Sorry, just re-read your sequence & that bit is now obvious. What do you use as a sanding sealer?
Yes, I sand through the grits, and then hit it with sanding sealer, then sand again then more sealer, thin coats. The sanding sealer I use is a lacquer based one, I thin it a bit, makes it easier to apply and it dries in a jiffy.Finished to 1/16" - Holey Moley! This must be almost translucent! Have you seen examples from the guy whose work actually lets some light through the timber? Can't recall his name.

Wayne

Answers in Red Wayne.

Thanks all! :B