How to hold this piece

[Jim Kountz]

Im working on the bowl in the picture, its going to be a segmented piece. Suppose I had all the rings glued up, how would you go about holding this for turning? The first two layers are just discs, the rest are 8 sided rings.

[Bill Embrey]

Not that I have ever done a segmented piece or have any vast turning knowledge, but my first thought would be a glue block on the bottom ?

[Jim Kountz]

Well I thought about that but Im wondering if things would get a little tight while turning the bottom portion of the outside. So I was first thinking of trying to hold it with the bottom towards the tailstock first then reversing it somehow and turning the inside. Dont know, still thinking!!

[Frank Kobilsek]

Jim,
Turn the back leaving a tenon larger than your intended foot. Flip into chuck and turn the inside. Now flip back on your vac chuck, cole jaws, ring chuck or just jam chuck to turn the foot and the portion of the back of the bowl that could not be reach when you orginally turned the back.

No sweat.

Frank

[Leo Van Der Loo]

hold it on the inside with a chuck, shape the outside, glue on a waste block and turn true before flipping the bowl over and doing the inside turning, then remove the waste block, should be quite simple in my mind, HTH

[Jim Kountz]

Frank how to mount it initially? Im with you about the tenon then reversing and all but Im not sure how to mount it to start. Its about 15" at the top so too big for cole chuck and I dont have a vac chuck yet so I dont know. On my smaller seg projects I just mount it with the foot against the headstock and turn the inside and outside at one time. With this one being so big I just dont know!

[Jim Kountz]

hold it on the inside with a chuck, shape the outside, glue on a waste block and turn true before flipping the bowl over and doing the inside turning, then remove the waste block, should be quite simple in my mind, HTH
How do I hold such a large opening in a chuck? The top is almost 15" in diameter and the ring is made of segments about 2" wide.

[Mike Lipke]

www.alanlacer.com

Then click on articles, scroll down to "how to make a Straka chuck"

Great PDF article on how to make one. Shows photos of 8" 16" and 36" chucks.
I just made one, and it is great.

[Leo Van Der Loo]

Jim the bowl goes over the chuck, and if you aren't able to tighten the chuck then you should make a flat disk for the bowl to sit over and use your tailstock to keep some pressure on it to prevent slipping, basically a jam chuck, that is held by your chuck.

[Hal Taft]

Jim,
You might try glueing a scrap piece on the top, to be turned off or split off(with a paper separator) after you turn a tennon and however much you want on the back. Or glue a tennon block to the inside, to be turned out after tennoning the foot.
Hal

[Jim Kountz]

Alrighty now Im getting some ideas! Thanks guys, I think Im going to give it a go. Wish me luck!

[Keith Burns]

Jim, this is how I would do it. I would glue a wast block on the foot and use a 2" face plate. Turn the outside and inside. Part the waste block off and since you don't have a vacuum chuck, use a jam chuck to clean up the bottom.

[Frank Kobilsek]

Jim,

I am not much of a segmenter, its one of those cases where my tools (table saw) and patience are not up to the job.

The first set-up for the back would be just like taking a rough turned dry bowl back to the lathe. Jam chuck the inside of the bowl against your chuck or a faceplate and support it with the tailstock.

Keith's idea is good too but I have had some my biggest catch ka-booms when I try to cut on the bottom of a shallow bowl when that side is in the chuck. Maybe its because I may allow too much tool overhang (past the tool rest) going that way. So not that its wrong I just have fears on that side. I can't use a skew either.

Frank

[Mike Golka]

Jim I have done a few segmented bowls like this and used a glue block turned down small enough to cover the base with a tenon that fits one of my chucks. I use the same glue to hold the block as I use for the segments( titebond III). Finish the bowl and then just part it off. I you want you can leave a small tenon and then saw and sand the rest.

[Bob Hamilton]

Hi, Jim:
If you haven't glued the rings together yet you could mount just the bottom disk(s) on a screw chuck, cole jaws or custom shaped wooden jaws to turn your tenon and maybe do some initial shaping. Then when you glue the other rings on top of the disks your mount is already there. I did something similar (only I turned a recess for mounting rather than a tenon) when I was making my dovetail bowl from a board:

http://bobhamswwing.com/Articles/economy/TRUE%20ECONOMY_files/image016.jpg

http://bobhamswwing.com/Articles/economy/TRUE%20ECONOMY_files/image017.jpg

If it is too late for that then I would use a screw chuck into the inside bottom if you have enough thickness that the hole will be turned away later or glue a block on to the inside bottom for the screw chuck.

Good Luck!
Bob

[Richard Madison]

Jim,
Please let us know which method you used and how it worked. The easy way was in amongst there (I think).