Can one of you tell me... *LINK*

Re: Can one of you tell me...

John Lucas

>revdoug

There are a lot of ways to reverse turn a bowl. The easiest as far as materials is to leave a center mark in the bottom so you can use a long drive mandrel that fits in the bowl to drive it and use the tailstock to hold it in place. you can't turn all of the bottom this way. You leave a very small cone that must be carved off.

I have also held the bowl in place with blue masking tape to turn the last little bit of the bottom.

We are going to have a group demo at my next club meeting to discuss this very topic. I will take photos and present them to this group next month. If any of you have any ideas I'll try to pass them on.

Here are some of the methods I use in a very brief description. Cole Jaws, a large wooden faceplate with maskinig tape or hot glue to hold it in place, a large wooden faceplate with a wooden Doughnut to hold the piece, Vacuum chuck, Turn the whole bowl between centers leaving cones inside and out that must be carved off.

Then there is of course using the chuck either in expansion or contraction mode and leaving this bottom. Except for the way Terry Daniels does it I've never been a fan of this method because there are either marks left from the chuck or the bottom isn't the right size.

Re: Can one of you tell me...

Joel Hunnicutt

>I've found a pretty easy method. I have a disc of mdf permenantly mounted on a facplate. I've covered it with neoprene and just pop it on the lathe and then bring up the tailstock like John suggested. I use it for anything I can't vacuum chuck and it works great.

Re: Can one of you tell me...

RevDoug

>All good and I am glad to learn this. But I would still like to know the max opening of the Nova Cole jaws.

Cole Jaws *LINK*

John Crissman

>I found a pdf file that puts the max opening on the larger Cole Jaws at 10".


Nova chuck pdf

Re: Cole Jaws

Richard Allen

>The large Vicmarc chuck can be fitted with button jaws that will hold a 19 1/2" bowl from the outside. Of course you will need a lathe with at least a 24" swing to use that chuck.

The large Oneway Stronghold with large button jaws will hold a 14" bowl from the outside. You need a 16" swing to use that setup.

You can put Oneway Talon button jaws on a Nova chuck which will hold an 11" bowl and requires an 12" swing.

You can make flat wooden jaws to the limit of your lathe. Put speed nut inserts and get a button set from Oneway. The Oneway buttons have a metal center which helps the rubber buttons keep their shape.

The best buttons I have used are the Vicmarc buttons. I don't know if you can by those buttons and screws.

The donut chuck works but limits your access to the part which is exposed by the hole in the donut. The button jaws don't hold as well be they are mostly out of the way and make it easy to "refine the shape" of the bottom.

A vacuum chuck gives the most free access to the bottom of the bowl but there are other issues like ring poures woods which need to be finished before they will hold a vacuum.

Good Luck

Richard

Re: Can one of you tell me...

John Leonard

>I just measured mine, It will hold an 8 5/8 inch diameter bowl in compression mode and 10 inch inside diameter in expansion mode. I almost never use it in expansion mode as the bowl usually goes flying. John L.

Re: Can one of you tell me... *LINK*

RevDoug

>Thanks guys, that what I was looking for.

Turn 'em round,

RevDoug


Wood Spun Round

Re: Can one of you tell me...

larry

>Something I often do is finish the bottom while the blank is still on the screw chuck. I usually leave 1/4" ring flat on my bottoms (picture (if I did it right)). I cover the entire bottom with masking tape to protect it from glue and with the lath spinning score the tape on the inside edge of the flat and remove the tape from the flat. I glue a waste piece to the flat, true it, reverse it and when done part off the waste close to the joint. Then take it to the belt sander and remove the last vestages of the waste.

Re: Can one of you tell me...

John Lucas

>Larry

I may be confused. You glue the blank to the 1/4" wide foot and then hollow the bowl.

Re: Can one of you tell me...

Dick Hines

>This has nothing to do with Cole jaws but may be helpfull.

To finish the bottom on small hollow forms I use a PVC connecter. The one I have is 2" on one end and 3" on the other. I put the 2" end into my chuck and a soft rag on the 3" end. Place the neck of the hollow form in the pipe and bring the tail stock up and finish the bottom.

Re: Can one of you tell me... *LINK*

RevDoug

>Sounds a bit precarious to me. Just doesn't seem like enough glue surface to be hollowing out a piece.

On top of that, what if your design thought changes and you decide you don't want that foot at all, or that it needs something larger?

Turn 'em round,

RevDoug


Wood Spun Round

Re: Can one of you tell me...

Doug Trembath

>Dick, a further refinement is to buy a sanding / routing pad, or some other soft rubber pad, and use it between the pvc and the vessel. I have a number of them cut in circles of varying sizes to fit jam chucks and vacuum chucks I use. It works better than a rag, providing improved friction and cushioning of the work. Won't hold a vacuum, though, but I took the advice from members of the group here about some craft foam available at Michael's this weekend to remedy that. Looks like it's going to work better than anything I've found so far, and it's $.79 a sheet. It would provide the same benefit as the foam pad in your case, as well.

Doug Trembath

Studio in the Woods

Re: Can one of you tell me...

Dick Hines

>I have some of the foam. I use for tieing fishing flies.

Re: Can one of you tell me...

larry

>That's correct.

Re: Can one of you tell me...

larry

>May not seem like enough, but it is, at least for me. I've done a lot this way and never had a problem.