How would you attack this bowl blank?

[dirk martin]

Please see the picture, as I'm curious about how others would attack this bowl blank.
Looking at the photo, let's call the top of the blank "side A", and the bottom "Side B".
This is Box Elder Maple.


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Let's assume side A is going to be the bottom of the bowl. In that case, I'd do the following:

1) screw side B to my faceplate.
2) Shape the sides, and put a tenon on side A.
3) Flip the bowl, putting side A's tenon into my Nova chuck.
4) Hollow out side B to about 1" walls, and then dry

Rather than create a tenon on side A, I could take a hand plane, and get surface A real smooth, and then use Gorilla glue to glue on a 1" thick piece of dry Ash...as a waste block. Then I wouldn't lose that inch of wood for the tenon. Am I correct with that thinking? Or, rather than using a hand plane, do you folks typically mount side B on the face plate, true up face A on the lathe, and then take it off and glue a waste block to side A ?

Next issue:

Maybe it doesn't make sense to make side B the top of my bowl. Maybe I should make side B the bottom of my bowl. That way I won't lose all of that red. So, what do you think of:

1) screw side A to my face plate.
2) true up side B, nice and flat.
3) Take it off the lathe, and glue a waste block to side B.
4) Remount with side A on faceplate, and turn a tenon on side B's waste block.
5) Flip blank, putting side B in Nova chuck.
6) Hollow out side A and shape to 1" thick walls for drying.

The blank in the picture is 12" diametre, 5" thick.

[David E Keller]

I think either way, I'd postition the blank between centers to try and balance the coloring in the top or bottom of the bowl. As to which side is up, I think that's just a matter of what you like. Regardles of which end is up, I think the finished piece will benefit from balancing the color. I generally don't use waste blocks, so I'd probably just turn a tenon and go from there. I'm looking forward to seeing that one finished.

ps. That would be a great piece for coring a couple of smaller bowls or a HF... If you've been looking for a reasson to buy one...

[Jim Underwood]

I second the coring idea. It's a real pity to lose all that color.

[Christopher K. Hartley]

Dirk, I would keep the color in the bottom of the bowl, otherwise you will end up turning away a good deal of this blanks beauty. If you did a hollowform as suggested you would be able to capture even more color. I would not use a waste block, but turn the tennon in the blank so as to have a nice foot. Just my thoughts.:)

[dirk martin]

Wow, I really thought everyone would say to use a waste block, to preserve more of the blank....so that's good to know that leaving a tenon on, is fine.
(I'll be roughing dozens of these, and then selling them, so it's good to know that having a tenon on them is good for most folks)

Plus I like hearing that you'd skip the waste block step, because I really didn't want to have all that additional time into these.

I really don't want to mount these, and balance the color, as it seems most folks prefer their blanks as thick as possible, and removing a lot of that white part of this blank on side A, will reduce the thickness drastically.

[Baxter Smith]

Interesting dilema. I woul agree with David on starting between centers to adjust as necessary to balance the grain and color if possible. The left side of the blank curves down quite a bit which might limit the size of a standard bowl keeping the pith/color in the bottom. Doing a NE might preserve a little more of the size and keep the color. Though the bark is gone, a bald NE can be just as pretty.

[Art Kelly]

If it isn't obvious from the start (is it ever?) which end should be the top, the only thing I DON'T do is screw on a faceplate*. If, unlike what you're showing here, the piece is small, I start out with waste blocks. That way the only material that is lost is the flat for the WB, and once you start you may change your mind, upwise.

I haven't tried Gorilla Glue and the gripes I hear about it probably wouldn't matter for waste blocks. I have used hot melt glue on every waste block since the first CA block came unglued at an inopportune time. Never had one come off. Yet.

Art
*There is nothing you can do to make an unwanted screw hole look elegant.

[dirk martin]

Seriously? Hot melt glue to hold on a waste block? Wow...that was unexpected. I like that, because it's fast and easy, but am suprised it holds. Cool. Using a waste block does save a good inch or so on overall bowl height, and every inch of height seems to please buyers.

[dirk martin]

Art, will the hot glue hold well enough to not require tail stock support?

[David Reed]

Please see the picture, as I'm curious about how others would attack this bowl blank.


I think I would sneak up on it in the dark shop and attack it with a sharp bowl gouge

[Thomas Canfield]

You did not give the blank size, but it looks to me to be about 6" or so. If the Side B, inside, is flat, then I would drill a 3/8" hole for worm screw in Stronghold chuck. If not flat, then I would use my 2 3/4" Forstner bit to get a flat spot for the 3/8" hole, tilting blank when facing if wanting to change the presentation. Mount blank on screw and turn outside with a tenon and dimple in tenon for later remounting or centering live center to remove tenon using a jamb chuck. Reverse the bowl and turn inside. The tenon only needs to be about 1/4 to 3/8" so there is not that much wood lost, and green wood is cheap. If the blank is green, then it needs to be turned thick, about 10% or diameter, and then dried before returning to end up with a round bowl. A glue block to me is useful for high price exotic wood or dry wood.

Another mount would be to use a 2 prong drive center on inside face to allow for adjustment of live center and then turn the tenon and outside before mounting in chuck.

[Art Kelly]

Art, will the hot glue hold well enough to not require tail stock support?

I've never tried it until the piece was round, but OK after that. In this post, http://www.sawmillcreek.org/showthread.php?154898-Pine-Galls-A-Preview... the pic on the left (scroll down a few posts for larger pics) was hollowed on the block after being bored to 1-1/4" with a Forstner. Of course, Pine galls are like turning cream cheese. I also did a 8" red-oak burl that had dried out for decades. it was like flint and stayed on perfectly.

This one was swapped top from bottom after I started:

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Bill Grumbine got me turned on to it. Somewhere he mentioned that he keeps an electric skillet full of HM glue so he can dip a piece into it. (Dangerous because the burns from HM are hideous.)

I've been able to get by with a cordless hi-temp gun, putting as much as I can get onto the wooden faceplate and pressing it on with the tailstock, or sometimes on the drill press.

Art

[Clint Baxter]

If you're planning on turning a tenon 1" deep, that is probably way overkill. if you seat the end of the tenon in a normal depth set of jaws, you're likely to get your blank off center. Typically, your tenon should be less than the depth of your jaws so you can bottom your blank against the top of the jaws. (This all assumes you're not using tower jaws and setting the blank deeply into them.) I think you'll find that most use a much shorter tenon than one inch. Depending on dry the blank is, you can often get away with less than 1/4". You probably want a bit more than that for your green turnings however.

Clint

[Dave Ogren]

Dirk,

If the blank is 5" tall and you do not want to lose any of the height how about a recess in the bottom. I am one of those who favors a foot on the bowl and turning a recess would be a natural. Most of the recess could be turned away when finished leaving a concave place on the bottom. Just a thought that I didn't see in the other posts.

Good Luck,

Dave

[Marc Himes]

Dirk, I would make side B the top and would make a tenon on the lighter wood. You can turn away much of the light wood and let the colored part of the wood be at the bottom of the bowl. This will make a shallower bowl but will preserve the colored wood and even allow it to be seen better than if the bowl was deeper. It is a beautiful blank and I am looking forward to the finished product. If you core out the piece may get you another 8-9" bowl but you will have to decide which piece gets the best color and I would favor the larger piece being the most colorful. I would probably start with a face plate on side B and turn a 1/2" tenon unless you were going to use tower jaws to get more support for coring. Then the tenon should be larger.

Good luck.

Marc Himes

[Rob Mathis]

I think I would glue on a waste block on the color end of your blank. Chuck it up between centers and cut it in about half. Then mount a face plate to the new surface I just made, and then shape the bottom with a nice foot/Tenon then flip it back around and hollow it out between centers. But that is me. I would try to capture as much color into the bowl as I could.