bowl bottoms

[Charles Bouchelle]

I have a simple question on something I am struggling on..Bowl bottoms.I turn my bowl with the blank on a faceplate,I leave a tendon to put in my chuck.I turn the bowl over, put it in the chuck to hollow.Than I have a problem....I sometimes put the bowl in my jumbo jaws and try to turn off the tendon....trouble I found with that, is that the bowl is not turning perfectly and I would mess up the foot.or I have tried to make a jam chuck and move my tailstock up to hold it...problem I have had with that, is the little hole created by the live center is deep because I am trying to keep it snug to hold it in the jam chuck set up,and I can't get rid of the little hole.Perhaps turn the tendon a little longer.Also if you are using the jam chuch method what are you using to get that nice indented foot It seems like the live center is really in my way.

[Steve Schlumpf]

Charles - check into donut chucks. Use your tailstock to align the bowl while tightening down the chuck and then you pull it back out of the way once most of the tenon has been turned away. That way you can finish off the center portion of the recessed foot area.

As far as pressure from your tailstock - you don't have to impale the bowl on the jam chuck - just firm it up so it doesn't slip. What size tenon are you using?

[John Keeton]

Charles, I just recently made a donut chuck, and it works great. I used it for a piece that wouldn't fit in the Cole jaws, and for which I couldn't use a jamb chuck arrangement.

But, for the last several bowls, I also have been using my chuck as a jam chuck. I widen the jaws to the appropriate width, and use a double layer of shelf liner to cushion the inside of the bowl. As for the hole from the tail center, the medallion I use in the bottom of the bowl covers that.

I start out with a blank using the worm screw in the chuck, and the tailstock. I finish turn the outside, with the exception of the area around the recess. Then, I move the tailstock, and turn the recess out for the medallion, and a recess for the expansion of the chuck.

Flip the bowl into the chuck and hollow it out and finish the inside and most of the outside, sand and apply finish.

The only thing I have left to do is finish the remaining portion of the bottom with very light cuts, turn away the dovetail for the recess, and add a little embellishment to the foot. Since the medallion recess has already been completed, I don't have to get in close to the tailstock center.

http://www.sawmillcreek.org/attachment.php?attachmentid=143240&thumb=1&d=1267138451 (http://www.sawmillcreek.org/attachment.php?attachmentid=143240&d=1267138451)

[Steve Trauthwein]

Charles,

I almost always use the jamming method even though I have donut chucks and made a longworth chuck. The live tail center I use has a small pin and circle which don't leave a big a footprint. You can get around a large live center by leaving more waste.

When turning the tenon off you can adjust the capture of the piece until it is very close to true. I usually turn this portion with a fingernail grind spindle gouge by cutting back toward the headstock very slowly at about 500 rpms. Patience is the key here. I will then make a finish cut taking maybe a sixteenth off, cutting across the bottom. Leave a small nubbin you can carve and sand off.

Regards, Steve

[Steve Schlumpf]

Charles - just in case you have not seen a donut chuck - here is a great PDF by Art Leistman on how to build one.

http://azwoodturners.org/DoughnutChuck.pdf

[Mark Levitski]

Charles, depending on what tailstock center you're using, on most you can remove the center point and just use the cup circle to hold your piece. The cup doesn't penetrate very far. If you have to use the point to center the tailstock, fine, but then remove it after it establishes where the cup should seat. Or, adjust the point by moving it further back into the cup so it doesn't penetrate so far. That way you don't have to mess with removing it.

Jumbo jaws, Longworth chuck, donut chuck, or vacuum system can all be used for this. However, like Steve says, the jamming method is most times the quickest and easiest.

[bob edwards]

All the chucks mentioned are valuable and deserve a place in your "Tool Bag" but there are times when the jam chuck method is the only way. A natural edge bowl is a good example. Consider that a jam chuck does not have to grip the project by itself. It is better used with the tail stock. I can't think if any project I don't start between centers. This gives me the opportunity to true up an align the piece for balance and to take advantage of whatever property of the wood I want to feature. My live center has a point which is removable but without the point it has a ring, circle or cup center. This leaves only a slight scar in the foot. This mark along with the tenon allows me to reverse and re chuck the piece as often as I like, never losing balance. The circle and sometimes the tenon is the last thing I remove before taking the piece off the lathe. I use this method for bowls, plates and platters, boxes, and hollow forms. Works for me!

[Brian Effinger]

Charles - just in case you have not seen a donut chuck - here is a great PDF by Art Leistman on how to build one.

http://azwoodturners.org/DoughnutChuck.pdf

And here is another that Alan Lacer uses: http://www.alanlacer.com/articles/StrakaChuck.pdf

[Ray Binnicker]

Charles,
Another solution is the vacuum method. I use it all the time and it works great for me. There are some really good home made ones, or several commercial models. I use the Hold Fast model (around $250.00). I do the donut chuck as the others have talked about, too.
Ray Binnicker

[Jeff Fagen]

Well you know what they say "some have inies and some have outies".
I make an inside tenon and fashon my foot ring and sand to finnish.
Then I don't revisit the foot till I sign it.;)

[Frank Van Atta]

You might look into a multi-tip live center like this: http://www.woodcraft.com/Catalog/ProductPage.aspx?prodid=329 In the version that I use, several tips have no center point and one has both a cup and a point that goes in only about 1/16" - I use this center quite a lot when I am only going to make a very shallow cut where the center is and don't want a deep hole. You can also use one of the centers with a central point to position the piece and then hold it in place while you switch to one of the cup-type tips to do the actual holding. This is the most versatile live center I have found - I use it almost exclusively while several others sit around just gathering dust.

One other thing; it you need a different tip than the 6 than come with it, make one out of a hard wood like oak or teak. If you need a shallow point imbed a nail cut short in the center. The possibilities are almost endless.

[Bernie Weishapl]

One thing you can do is to get a adapter that your chuck will screw onto and will be put in the tailstock. Leave the chuck attached to the bowl and remove both from the headstock. Put the hole part of the donut chuck on before inserting the adapter and chuck with bowl into the tailstock. With the other part of the chuck on the headstock bring up your tailstock to just before the bowl touches. Lock your tailstock down and crank the bowl up to the chuck. You don't have to strong arm it. Then bring up the hole part, insert screws and tighten down fairly snug. Loosen the chuck and pull away. Your bowl is centered and you have access to the bottom with no livecenter mark.

You can use a donut chuck on NE bowls with a jam chuck inside the bowl opening then brought up snug to the donut chuck. Clamp into place and finish the bottom.

[Robert McGowen]

Once you use a vacuum chuck, everything else will seem like a waste of time!

[Paul Atkins]

Please don't put your tendon in the chuck!

[Allen Neighbors]

Charles,
When I turn between centers while making the tenon, the hole left by the spear point is too large to fit the tailstock center point. So I sand the tenon on my 80 grit belt sander til there is just a small dot of point left for the tailstock. Works well. Centers up really well that way.