question: when turning a tall vase shape, how to do the bottom?

[Greg Ketell]

A friend gave me a chunk of Red Gum Burl and I want to turn a small, natural-edge vase out of it. But for the life of me I can't figure out how I would hold it to finish off the bottom of it.

I'm thinking of a shape somewhere between
http://www.xmission.com/%7Eburlturn/gallery/thumbs/Copy%20of%201%20005.jpg and http://www.xmission.com/%7Eburlturn/gallery/thumbs/NE_Jarrah_Vessel.jpg
(Photos from The Burl Source clients' gallery http://www.xmission.com/~burlturn/gallery/gallery.htm).

How do you reverse-chuck something tall, porous, and with a rough top opening?

Thanks in advance for any suggestions!
GK

[Thomas Canfield]

Greg,

Take a look at Don Pencil Jam Chuck. You can make different adapters for hollow forms but it still requires the use of the tail stock and you end up with a small nub. Kelly Dunn recently posted on another site using a ring behind the chuck with a jam piece going to the inside bottom, and a modified donut type ring used to hold the piece. I haven't tried it, but it looks like the Pencil Jam Chuck will work inside the #2 MT with a chuck mounted. Something to think about. Keep us posted.

[David E Keller]

I've done sort of similar pieces by using a long turned spindle as a jam chuck. It try to make the spindle just barely long enough and narrow enough to reach through the opening and just touch the bottom of the vase. Slow speed, light cuts, and sharp tools. It leaves a little nubbin that I deal with by hand.

Although I haven't done it, you could use a steady rest at the same time for extra support.

[James Combs]

I would think that a donut and jam chuck combo would do the trick all though I have never done it myself.

[charlie knighton]

craft supplies sells a woodchucker mandrel, not cheap but wooks very well with the tail stock pulled up

page 37 of spring/summer 2010 issue

[David Woodruff]

I typically use a vacuum chuck. For a piece like this I would try the long, large diameter. If not then a soft mouth vacuum chuck inside the openning. Bearing in mind that the vase provides good leverage to break the seal. I always use a revolving center that has .25" footprint on the bottom. Finish all you can to the center, carefully backing off the bottom center to finish the very center. If the beast leaks do the a forementioned to the point of finishing the very center by hand. Hand finish the nub carefully and you will not know the difference. I frequently use a vacuum chuck as the drive chuck sans vacuum when finishing a piece that has holes and leaky things. Note to, that duct tape does a good job of sealing, enabling use of the vacuum. I have on many occassions completely wrapped the work piece to enable vacuum chuck use.

[Tim Rinehart]

Greg,

The replies so far will all work to some degree or another, but most will require you deal with the nub on the end, where the tailstock live center was inserted.

Depending on your 'top' shape, if closer to the first picture, a vacuum type chuck is what I use, seating that foam tape on the end of a piece of PVC pipe against the top shoulder of the form, and then taping the dickens out of it. If you have a fairly solid piece...a vacuum hold itself will often suffice, perhaps with a little shellac, lacquer sealer or tape applied to seal of light porosity in the piece.

Once you have everything but the nub left, very light cuts and having the piece held on by tape has worked very well for me...and leaves ability to add little embellishments like a couple of point tool circles in the end as well.

Obviously...tape has it's limitations and you have to decide if it will work for your piece, or if a chisel and small sanding discs is in order.

I have seen the described tool by Don Pencil in a home-made variant...and it looks like a good technique...but I haven't had the need for one yet and I've done several deeper HFs (up to about 10 inches or so), though not one quite like the second picture.

Good luck!

[Bernie Weishapl]

I made a Don Pencil style and it works pretty well.

[Allen Neighbors]

I don't know what they're called, but I use a gizmo that I copied somewhere... (I never have an original idea).
It's a cone-shaped piece with a center rod that is held by a set screw. The top of the piece goes against the cone, to center it. The Rod end, leather covered, goes inside the piece, all the way to the bottom. That way, the end of the rod takes the pressure of the tailstock, not the fragile top.
Then you trim the bottom the way you want it, and all you have to do is hand finish the little nub.

[Greg Ketell]

Thanks all!!

Since I have a vacuum chuck I'll try that to start with. If that won't work I'll make a "don pencil"esque jam chuck. Heck, I might even try to get creative and make a Don Pencil vacuum jam chuck.

GK

[Leo Van Der Loo]

I'd use the setup Allen is showing, the bottom held between the shaft and the tailsock center, and the neck part/end steadied by the wedge type plug.
If it is fragile like you are suggesting the vacuum could collapse the vase, ..........also the area of holding is very small as only the area of the vase that contacts the chuck is all that counts for holding, not the body area.

[Gary Conklin]

http://www.laymar-crafts.co.uk/tip38.htm

[Neil Strong]

http://www.laymar-crafts.co.uk/tip38.htm

Good reference, thanks Gary

.....

[David Woodruff]

Please just send it to me and I promise a fitting finish. Really!!!!!!!!!!