brehaut

[brehaut]

Hello everyone. I am Dave Brehaut and live in Stafford VA. In mid November my dad and I took a turning class at Woodcraft and I am hooked. Started practicing on the lathe at work when time permitted and in mid Dec I bought a lathe. Have made several ornaments, boxes, bowls and goblets and have even managed a few captures rings. For the most part all has been going well.

What my questions are...

1. what is the best way to remove or dress up the tennon on the bottom of bowls. after turning the outside, chucking it up to turn the inside and basically completing the bowls i am left with tennons (short and bowl foot size) that have chuck marks that need to be fixed or that need to be removed all together to improve the appearance of the bowls.

2. I have a couple of end grain bowls that were made from ornamental cherry that has been in the firewood pile for 2 1/2 years and is beautifully spalted and wormy and buggy. the problem i have is how do i stabilize the pith to prevent further cracking and splitting.

Any help would be greatly appreciated.

I will post pics of the bowls soon. I think they are real neat.

 

[Steve Sloan]

Dave, welcome to the insanely addictive world of wood turning, or as my wife calls it, new tool buying. For cleaning up the tenon or foot on the bottom of a bowl, I like to chuck it jumbojaws. I have these on their own chuck, so once I've finished the inside of the bowl I swap chucks and put the bowl on there to finish the foot.

As for stabilizing the other bowls, one way is to saturate it with thin CA glue. Maybe not the best way but it should work.

Best of luck.

 

[Joe Greiner]

I skipped the jumbo jaws and went directly to making a Longworth chuck - a scroll-like affair to grip the rim. There are several plans available on the Internet. But before that, for a while I used a disk of plywood mounted on a faceplate. Turn a groove to mate with the bowl's rim. Set the bowl in the groove, and wrap several strips of tape (masking or duct OK, filament best) from the back of the disk, across the near bottom of the bowl, and over to the back again. You can reinforce the back attachment with staples into the plywood. This basic idea is shown in "Lathes and Turning Techniques - The Best of Fine Woodworking," ISBN 1-56158-021-X, page 111, by none other than Betty Scarpino, the current editor of AAW Journal. Re-turn new grooves as needed for later bowls, and when that's no longer feasible, replace with another plywood disk. Even with Longworth or jumbo jaws, the tape is good insurance. If you fold about 1/4-inch of tape back upon itself, you've got a handle for easier removal.

I think it's best to remove the tenon completely, and dish the bottom slightly, to form a foot ring - more stable than flat. Score some fine grooves within the dished part to pimp the bottom if you like. It's also best to resist the temptation to work a little way up the sides; re-mounting is almost never concentric, and re-cutting there will create a mess.

 

[Vaughn]

I have a vacuum chuck and various donut chucks, but more often than not, I use a roughed-out bowl mounted on the chuck as a friction chuck, and use the tailstock to hold the finished bowl in place. The roughed-out bowl can be larger than the finished bowl (to fit outside of it) or smaller than the finished bowl (to fit inside of it). The smaller bowl trick is especially handy for natural edge bowls. One the finished bowl is held in place securely, I turn the tenon down to a small conical nub, then either make the final cut with the lathe at low speed or do it with a sharp bench chisel off the lathe. A minute or two with a power sander and any traces of the nub are gone. Like Joe, I like a slightly concave foot (or a recessed convex that matches the curve of the bowl, yet has a "foot ring" around the perimeter of the foot).

 

[john lucas]

I have all of the above but still use the first method I learned. I simply put a rubber pad over the chuck or faceplate,place the bowl over this and bring the tailstock up to hold the bowl in place. Then I just turn all of the bottom except a very small tenon where the tailstock is. I carve this away after the bowl is finished.
Since I start every bowl between centers with the bottom toward the tailstock there will still be a center mark which makes it very easy to align. This is much faster than hooking up the vacuum or putting on one of the jumbo jaw chucks.
Occasionally I will have to shape the bottom differently and can't leave this center mark or tenon because they won't fit in my chuck jaws without removing this mark. I have one of those devices that fits in the threaded insert of your chuck and has a centering pin. Before I remove the chuck from bowl I simply insert this and make a mark. Then it's still very easy to reverse mount it.
If you don't want to buy one you can make one very easily. Simply turn a piece of wood down to fit accurately into the threaded insert. Center drill this. Then take piece of steel the same size as your centering hole and sharpen it. I do this by chucking it in my hand drill and holding it against the stone. That keeps the point centered.
An even better option is to take a piece of threaded rod the same pitch as your spindle. Center drill this and make the center mark pin. This is more accurate as long as your able to drill the hole in the center of the threaded rod.

 

[MichaelMouse]

Some pretty elaborate and involved answers, that's for sure.

Every time I tried to look at the bottom of the bowl I spilled the contents, so I decided that I wouldn't spend a lot of time and effort doing something unnecessary. So I don't.

http://i35.photobucket.com/albums/d160/GoodOnesGone/3-Ash-Plate.jpg "Foot."

http://i35.photobucket.com/albums/d160/GoodOnesGone/CIMG_2236.jpg It's actually the second ring, not the third or fourth, though it could have been.

http://i35.photobucket.com/albums/d160/GoodOnesGone/WCIMG_1243.jpg Almost no depth lost.

http://i35.photobucket.com/albums/d160/GoodOnesGone/Bark-up.jpg A bit of a stand-up circular reveal, flattened after drying by a block plane.

The mortise method is good on a number of levels. First, it allows a deeper bowl from the traditional half-log than a tenon. Second, it shrinks when the wood dries, so you don't have to fuss with weighing all the time, you wait until the mortise has lost its 1/8" in two, then weigh. Third, you don't have to imagine the exterior contour, then re-cut after you face chuck it again. Avoids the step-pyramid effect as you try to blend the bottom to the sides. What some call "love-handles."

It does presume some sort of top-mounting capability for the after-dry which you can do with a pillar and a pin chuck as I use, a woodworm screw as some might, a chuck capable tenon, or a complete between-centers mount with the drive center, as some (not I) use.

It's good enough for me, and customers don't seem to care. Easy to do, as here, where the thin parting tool cuts the mortise round, the gouge trims and smooths inside, and the beading tool makes a couple ornamental cuts. If I had planned for it, I could have held the farther ornamental as a tenon by cutting in a bit. If it's right-sized there are no marks left with a smooth dovetail.

http://s35.photobucket.com/albums/d160/GoodOnesGone/?action=view&current=BottomHoldProcess.mp4

Another way of doing things.

Almost forgot. You can fill the cracks with splinters in the proper orientation, held in with CA. Or you can fill and flash with contrasting medium like bark or one of the non-wood inlays. Keep it tight, and be prepared to reinforce if you reveal new ones. Cherry doesn't spalt here, so a picture would be nice.

 

[Wipedout]

Check out this how to make a donut chuck

http://www.nealaddy.org/node/42

 

[brehaut]

Thanks to all

for all of the great info. i will post pics of the cherry pieces this weekend.

Daveb
NOOB

 

[Gretch Flo]

Every time I tried to look at the bottom of the bowl I spilled the contents, so I decided that I wouldn't spend a lot of time and effort doing something unnecessary. So I don't.



It does presume some sort of top-mounting capability for the after-dry which you can do with a pillar and a pin chuck as I use, a woodworm screw as some might, a chuck capable tenon, or a complete between-centers mount with the drive center, as some (not I) use.


http://s35.photobucket.com/albums/d160/GoodOnesGone/?action=view&current=BottomHoldProcess.mp4

Another way of doing things.

Michael-I used to double turn-not any more to avoid this issue-that is the round mortise that has become oval. I too am like you in that I don't carve off the chucking "method". As others have stated here, noone except other turners pay any attention to this- I just make a decorative middle "button"-which is a raised area I can etch my name in the end. The recess allows writing the name of the wood and where the wood was obtained from-also allows price tags to stay better where they are not knocked off by storage. Occasionally I get a wood that doesn't sand well in the recess.
.I have a talon chuck (3 of them with diff jaws on them), I have the coles or jumbo jaws as well which are terribly labor intensive to get the rubber thingies in the right spot. I do alot of natural edged bowls as well. Most of my bowls are 12" or less. I don;t leave a piller like you do.
My question is how to hold it to make the oval mortise round again. (My jaws are not dovetailed) The pinching method doesn't allow me room with the tail stock in the way.
I Used to just chuck with the oval hole, used the tail stock for retruing the outside, and maybe part of the inside. and it would work most of the time. I don't double turn anymore, but have probably 100 bowls 4-8 years "dried" that are just waiting for me to tackle again. Too busy with newer wood. Did return some from 2003 a couple of weeks ago, but there wasn't much warpage and mortise still mostly round.
Hope I have made myself clear, sending photo is too much effort for me!!!!!!Gretch

 

[john lucas]

methods for reverse turning bowls

I forgot I had written this to put on our club websits tips pages. Look under Methods for reverse turning bowls. You will find a wide variety of methods. Hopefully one will work for you.
http://www.cumberlandwoodturners.com/htm/tips.htm

 

[MichaelMouse]

After drying you have to have some way of re-mounting, and as close to true center as possible. Hopefully you have your artifact center mark inside the mortise or in the center of the tenon for that side. You then require either the pillar with a center used in the original rough, or an artifact center mark in the inside of a fully hollowed rough. You can then chuck up a wooden center like the turners of old used to drive and hollow, only in this case, at the headstock. http://www.robin-wood.co.uk/ Shows one on the tail. If you plan a bit ahead, you can have this within 1/16 of true.

I favor my pin chuck because it's so easy to start a green piece, re-bore and mount a dry one. I don't need the other center and my hollowing scraper to reach around into the mortise, which is my favorite mode of attachment. Tenon people would have things easier. http://i35.photobucket.com/albums/d160/GoodOnesGone/Method-One.jpg

Alternative method using pin jaws, though they don't go as deep as the pin chuck to hold against droop, though I have successfully held a full 16" rough cantilevered on them. Second-handiest jaws out there. See the flat cherry posted above for one example.

http://i35.photobucket.com/albums/d160/GoodOnesGone/1-Ash-Plate.jpg

http://i35.photobucket.com/albums/d160/GoodOnesGone/2-Ash-Plate.jpg

Three way's I've played the game, though the woodworm/pillar combination would certainly work. Just never liked the woodworm!

 

[Gretch Flo]

Thanks, Mark and John. One question I have about the worm screw ( wood worm screw with the Talon), is that rescrewing you often end up with blank wobble if it isn't seated exactly with the same amounts of
thread.
For instance, If I for some reason, need to put finished outside of the blank back on the screw (most reasons are that I have not made the mortise deep enough or the rim cracked when trying to start the hollowing process. If I rethread back, it is usually not the same and the outside of the finished bowl wobbles. I don't have to do this very often. Gretch

 

[MichaelMouse]

Wobbles probably because the contour of the surface that you're butting against the nose of the jaws changed. Level it and it'll work much better.

 

[Gretch Flo]

Wobbles probably because the contour of the surface that you're butting against the nose of the jaws changed. Level it and it'll work much better.

That probably is the reason-On nat edged bowls I chisel a "flat" area. Sometimes, being small contour, the chuck rim surrounding the worm screw sometimes does not make full contact. I'll try to do better-esp on suspect (spalted, pity, soft etc) wood. Gretch

 

[Bill Boehme]

Every time I tried to look at the bottom of the bowl I spilled the contents, so I decided that I wouldn't spend a lot of time and effort doing something unnecessary.

Well, MM you are supposed to reach in your purse and get out your compact and use the mirror to look at the bottom. The guys in my turning club are always flipping my turnings over to see what the bottom looks like. I don't know -- I guess that the top ain't good enough for them and they gotta' see if the bottom is any better. Maybe I should spend most of my time working on the bottom and leave the top rough.

In the old days, they just glued a piece of green felt to the bottom to cover up the screw holes.

Since the rotary adapter recently broke on my vacuum chuck, I took a step back to my previous method -- I turned a jamb or jam (depending on who you ask) chuck that has a contour to match the bottom of the bowl and then use a paper towel or something slightly soft with grip to go on the inside of the bowl and bring up a cone point on my live center to the bottom of the bowl. I spend a bit of time getting this aligned, but it is rarely perfect. Next, I gently turn the bottom to whatever I want. There will be a tiny nub in the center which I break off and sand smooth.

Some people turn a recess to attach the chuck. I have done it a few times, but still prefer having a tenon.