My take on turning the bottom off a Hollow Form

Stuart Ablett

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Tokyo Japan
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 :D 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.

hf_turn_off_2.JPG
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

here is the nearly finished piece....

hf_turn_off_6.JPG hf_turn_off_7.JPG hf_turn_off_8.JPG
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. :thumb:

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!
 
Nice idea Stu.

I've also made a large jam chucks to hold pieces to aid in cleaning up the bottom.

Later the jam chuck would be turned into a bowl.
(I wish I could say this was my idea, but I read it somewhere)
 
Nice, Stu! Jam chucks come in very handy in my shop. I have enough oak laying around that I usually just keep them as jam chucks. Never know when I might need another.;)
 
Stu, that is the traditional way of removing the tenon or chuck recess on the bottom of a bowl or hollow form.

A friend of mine showed me another way that I like that is fast and so far works fine. I am sure there are shortcomings to it but it does seem to work

Laminate a couple of pieces of MDF together and attach them to a faceplate. True up the MDF and glue some carpet padding to the face with rubber cement.

Now you can just reverse your bowl or hollowform against the rubber on the large faceplate and bring up your live center to hold it. The rubber covered faceplate drives the piece without damaging it and the live center holds it in place and allows you to remove the majority of the wood you want to remove and finish the bottom except for the nub left after you remove it.

Here is a picture of it in use....
 

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Hi Stu,

Another approach is to glue a block onto your dougnut chuck and turn it into a cone shape. It won`t interfere with you regular bowls, so you get two for the price of one.

Gari

P.S. I`m been vacationing in Japan for the past four weeks. Another four before I head back to Vancouver. I`m getting cold turkey from the lack of turning! :(
 
If I don't use the donut, my approach is usually about like Big Mike's. I just mount the back plate part of my donut chuck (3/4" ply on a faceplate) and use pressure from the tailstock to sandwich a piece of closed cell foam between the plate and the turned piece. The foam's not glued to the backing plate, but I've used successfully this for both hollow forms and bowls.

If it's a hollow form with much of a collar, I'll also sandwich one of the smaller rings from my donut chuck between the piece the the backing plate. This way the tailstock pressure is on the shoulders of the vessel, not the collar. Here again, just friction, no adhesives.

Donut Chuck.jpg

I intend to turn myself a cone so I can try out Gari's suggestion, too.
 
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