Finishing bowls with recess rather than tenon

[Dan Forman]

I have mostly used tenons on the bottom of bowls, but I did try a recess with a couple of them. I now realize that its much easier to true up a tenon than a recess, as I can use a jam chuck with tailstock to true a tenon, but no such luck with a recess, as the tailstock won't permit access to the recess.

I assume a donut chuck is necessary to hold the bowl for this operation, but does it not matter that the bowl is warped at this stage for truing the recess? Would a vacuum chuck be unable to hold the bowl due to the warp factor?

Dan

[Harlan Coverdale]

Like you I'm mostly a tenon turner, for the reasons you've discovered. I think recesses are more appropriate for turning dry wood, or turning green wood to final thickness in one shot, then letting the dry and warp as it wants. But that's just personal opinion, YMMV.

The times I've used a recess, I re-trued it with the tailstock in place, planning to take enough off the bottom when finishing it up to remove the live center divot. I must have been using a bigger recess than you, because I was able to get to it, barely. I'd think you could use a donut chuck, and just monkey around with it to get it centered as best you can.

The vac chuck might work on some bowls if they're not too warped or rough. I think that would vary on a case by case basis.

[Mike Minto]

funny, i was dealing with this very situation just yesteray. when i turn green wood, i, too, almost exclusively make tenons; on this particular bowl, i had to turn a recess because the original tenon i had made in it had ripped off during some overly enthusiastic roughing out. anyway, having dried for half a year or so, i remounted it directly into the recess using my SN2 chuck, expanding the 50mm jaws; the recess had warped hardly at all, much to my surprise. the unfortunate result however, was a good quarter of the 8" bowl ripping off and flying by me at a pretty good clip. no injury to me, but the bowl is unsalvageable. just wasn't meant to be; oh, well. mike :mad:

[Chris Rae]

I built my donut chuck with an adaptation so I could use it for NE bowls, I think it should work for warped ones also. Center piece unscrews for regular bowls.

[Mike Minto]

chris, you are quite the engineer! i have started, but never finished making a donught chuck - guess i ought to finish it. mike

[Harlan Coverdale]

chris, you are quite the engineer! i have started, but never finished making a donught chuck - guess i ought to finish it. mike

They're pretty easy to make, inexpensive, and very handy. The hardest part is making the round parts, but most of us have a great tool in our shops for making round parts already. ;)

[Leo Van Der Loo]

It is an exception if I use a tenon, my bowls are turned with a recess most often, as it has a mechanical advantage, and I hardly ever use a tailstock when roughing or returning.
Usually I re-chuck a dried roughout and flatten the rim, then use the mega-jumbo jaws to hold and return the recess and often also the outside of the bowl, before returning the inside, it all depends on how and how much the rough piece has warped, it calls for other means at times.
Now if I turn on my Delta midi, and need to return a recess (I have no jumbo jaws for it) I use a simple small tool I made for it, I used a cheap little tool and ground a corner out on the side, so that I can hold the tool at an angle and make the recess round and square again, I'll make and add a picture.
You also could make an extension for the front of your live center so that you'd have more room to get in between the workpiece and the center point, though I never had to do this yet.

[Frank Parker]

I use a recess all most always, I've turned several hundred bowls and I may have used a tenon 6 times and at least 3 of those the tenon snapped off sending the bowl flying across the room. the only time I use a tenon is on end grain turnings. The recess also means that the bottom is already halfway done. As for having to true up the recess, about 95% of my turning are close enough to lock on the jaws solidly. Their not perfect so it means that once I start it doesn't come off the chuck until it's finished. As for the other 5% I do as Leo does. On a couple of occasions I've even used a dremel to clean up a recess.


Frank

[Bill Bolen]

Chris, that is a great idea for NE's! Mind if I copy?...Bill...

[Ryan Baker]

Chris, another tool-making gold star for you. Nice design with the donut chuck.

[Ken Fitzgerald]

I use something similar to what Chris uses. I use my donut chuck and I turned a funnel/cone out of foam insulation. The funnel goes on the base of the donut chuck...the NE is placed over it and then the donut part of the chuck captures the NE between the cone and the donut.

[Chris Rae]

Copy away Bill!

[Dan Forman]

Thanks for all of the suggestions. I picked up the materials for a donut chuck tonight. I saw a tool similar to the one that Leo made, but didn't think there was room for it, but recreating the setup, I think there might be. Wish I had picked it up last night. :(

Still, a donut chuck should prove useful, so will see how that goes. I'll include Chris's option to account for warp. Thanks Chris!

Dan

[Jim C Bradley]

OK Chris, I will again express my ignorance as a newbee to turning. What does NE mean? It is not on my list of SMC abbreviations. Yes, I do realize that I am going to say to myself, "I should a known that."

Enjoy,

Jim

[Ken Fitzgerald]

Jim,

It means Natural Edge.....in bowls...the blank is turned the opposite way and the bark is left on the rim of the bowl....or goblet....or hollow form..HF..... Normally you would have the bottom of the bowl at the outer edge of the tree and you'd turn the bark off.
Look at Chris's photo. The rim of the bowl is not in a flat plane either because of the curve in the outer edge of the tree/blank...

[Leo Van Der Loo]

NE = Natural Edge ;-))

[Chris Rae]

Hi Jim, NE means natural edge. It took me awhile to learn all the abbrev. that turners use. Even now I sometimes run across one I have to think about.

[Chris Rae]

Wow, 3 of us within a minute!

[Dan Forman]

Chris --- How does the center thingy screw into the chuck?

Dan

[Reed Gray]

For me, I use a smaller extended jaws chuck to expand into the recess. Since the recess is oval after it dries, if you rotate the bowl a bit you can get 4 jaws on the recess. This does give a good enough grip for sanding, and maybe some gentle rim truing, but I would not try to return a bowl this way, just not a secure enough grip.

robo hippy

[Chris Rae]

The donut chuck is mounted on a face plate which has a hole in the center of it. I drilled a hole in the plywood to allow for a short bolt to go through the center of the faceplate and come through the hole in the plywood. I drilled a hole in the center thingy and epoxied a nut in it to screw on to the bolt. I also mounted a washer flush with the surface of the wood to save wear on the wooden hole. You just have to make sure the head on your bolt will fit in the hole in your spindle or grind it down until it does. I hope I've explained well enough for you to understand.

[Dan Forman]

Yup, thanks Chris.

Dan

[Mike Lipke]

Great and detailed plans for a donut (Straka) chuck:

http://www.alanlacer.com/articles/StrakaChuck.pdf