Bowl not sitting flat

[Kevin Nee]

Hello, I recently turned a White Oak Burl bowl. It was from a piece of burl that had been sliced at a band saw mill.
It is about 10 X 4. It came out quite nice. I brought it in the house to show my wife. It sat on the dining room table
for at least a week. Now I have a little rocking as it has moved a little. My question is could I remount it on the lathe?
I used the Oneway super jumbo jaws to do the bottom. Am I asking for trouble by going back to the lathe. I have
enough thickness. This piece of wood had been sitting in my barn for about 3 years Thanks in advance, Kevin

 

[robo hippy]

Wood moves, constantly. How much depends on how much the humidity changes. The only way to keep it from ever not rocking a bit is to make a 3 legged foot on it because 3 points make a plane, and it will sit flat. Any flat turned bottom will still warp and move. Flat one day, warped the next. I do try to make the bottom slightly concave which helps a bit rather than dead flat. Also, you may find that it can sit flat on one table, and not another. This can be the surface it is sitting on.

robo hippy

 

[Kevin Nee]

Thanks for the response. I am aware that concave is the way to go. I tried it on a granite table, a large piece of tile, and a wood table
Still pondering putting it back on the lathe. I would like to sell it this week-end.

 

[hockenbery]

If your bowl has a foot this might work.

When I turn hollow forms and natural edge bowls with a foot or a recesses they are still moving and warp as they dry.

The bottom of a foot is typically a ring 1/4. Wide with the center cut out as a recess. The foot Itself is anywhere from 1" in diameter up to 3"
To true the foot once these are dry I clamp ( two spring clamps) a sheet 220 sandpaper to my table saw which has a nice flat surface.
I then slide the foot over the sandpaper with the grain. Be very carful not to rock the bowl or hollow form. This is harder than it sounds but an achievable goal.
Make the first couple passes with little pressure then as the foot's bottom is getting flat increase the pressure just a bit.

5 passes is usually enough to flatten the bottom


This also works with a simple recess but you get two opposing crescent shapes on the sides of the recesses.

Al

 

[hockenbery]

PS
I do round bottoms on most of my natural edge bowls and most of my hollow forms.
So much easier to sand and deal with.
Round bottoms only rock when pushed and not that much.
They are in keeping with Native American pottery shapes. This may help with the next one



Al

 

[Steve Worcester]

before i am finished with the foot of a bowl, I always put a straight edge across the bottom. Concave wins that race.

With that said, if it is wet wood, all bets are off.

 

[robo hippy]

Even if the wood is dry, it will move with seasonal and humidity changes. This is why you can not fix a solid wood panel/table top down tight. It has to float, or either the panel or frame will break eventually. Woodworkers in Arizona and Palm Springs make a lot of money 'fixing' wood pieces from other parts of the country that are moved in.

robo hippy