Hollowing Out a Vase

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Hollowing Out a Vase

Postby stephanmoll » Thu Dec 25, 2014 4:00 pm

Now I really need help/advice - and if it is only an "impossible to do this".

Started on my first ever wood-turned vase; beautiful cedar wood that I picked up this summer from a WGNC member's back yard in Durham. Started to turn the piece and got carried away, not looking/planning much ahead. Now I am left with the form of a vase (image 1), but only a small tenon (image 2); not big and thick enough an area to screw a face plate into. The vase is 10 inches long; I expect that the force of the hollowing tool in action would leverage the vase out of the chuck (image 3). What to do now? I doubt a piece of wood glued to the foot of the vase will be strongly enough adherent to the vase that a face plate screwed into that extra piece of wood will remain attached to the vase throughout the hollowing process, right? Any advice?

The second, yet less burning question: since the opening of the vase is small and the chuck for the drill is wider/thicker than the opening (image 4), is there any extension piece that one can use to be able to drill all the way down close to the bottom of the vase? Or any other trick?

Thank you very much. Seems like one should ask Chris Boerner whether he'd be willing to hold a workshop entitled "Turning big hollow objects". Or one could have an interesting, more global topic of "Turning big objects". That would be very relevant and fun.

Cedar, Durham; 10'' tall


No space for a face plate


Hollowing out won't work using a chuck, right?


How to extend the drill, to be able to bore to 19.5'' deep?
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Re: Hollowing Out a Vase

Postby normcloutier » Sat Jan 03, 2015 10:34 am

Hi Stephen;

Somewat familiar with this. In fact, I think you and I have the same lathe (Nova DVR?).

Chris is indeed the expert, but with cedar being so oddly soft AND brittle you will need a more substantive holding. That small tenon in your photo would never hold up to hollowing. After about 6-8" of length you really need a faceplate attachment, in my experience. Some people do have special jaws that can hold a huge (depth) tenon but I don't have that option. Also, for end-grain you want to use machine screws instead of the wood screws you use on face grain

In your case, since you have not yet hollowed, I would rework the shape and leave the bottom 2 inches (above the existing tenon) for faceplate attachment.

As for drilling, you can buy extensions for Forstner bits but bear in mind the integrity of holding center drops a good bit as you stretch. I've also found that cedar doesn't drill all that well. Tends to generate more heat and dust than shavings, but it does work if you are patient. Keep speed below 400.

Here's my first serious attempt at hollowing -- and with cedar -- from 2011. Not by best shape, but I went with a 2-part form to make my first hollowing more reasonable.
2011 cedar hollow form
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Re: Hollowing Out a Vase

Postby marcbanka » Mon Jan 05, 2015 7:21 pm

Stephan,

1st point: Any statement of opinion or art should be taken with a grain of salt, and may change without notice. I'm self taught, so rely on empirical data heavily.

That's a lovely shape. It'd be a shame to have to give up or change it radically.

The drilling.
It looks like you have enough room, at the throat, to pass the drill chuck and leave enough for a good wall. Why not use a Forstner bit slightly larger than the chuck? Drill as far as the throw on the tailstock will allow, using Norm's suggestion of slow lathe speed and a sharp bit. Then starting again with the tailstock retracted, move the tailstock (lathe off) into the throat of the vase, lock it down and continue drilling. Just make sure you withdraw the whole mess often, to clear shavings. I would be a bit conservative with the depth. You can always cut deeper if needed.

Hanging on to your work.
Nova makes a nice chuck. However the tenon gripping on the standard jaws sucks, alot. No way will it hold that short tenon on your piece. If you have serrated jaws, like the standard jaws of the inferior PSI chuck, you would fair much better. I found this through trail and error. The difference is huge.

Good luck with the hollowing. That's an ambitious depth. Slow and easy!
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Re: Hollowing Out a Vase

Postby stephanmoll » Sat Jan 10, 2015 2:21 pm

Thank you, Norm and Marc. The other option is this: Do not hollow out and just enjoy the outer form and wood structure. I'll see what I'll do.
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