Returning Bigger Warped Bowls

[Sonny Kemp]

What a mess Im in now!!!! I went from a 10 in lathe to a 1624 Nova to make me some bigger bowls. Well Ive got me a pile of what were about max capacity on the 16 inch Nova when I started to dry them ,that are now warped too bad to rechuck and finish turn.Any solutions?I never gave a thought to how much they were gonna warp!!

[Roger Chandler]

Yep....that is the purpose of twice turned bowls. Turn thick, let dry & warp, then when dry put back on lathe and re-turn to round. You have to leave enough wood in the initial turn to allow for the second one. Usually about 1/10th..........a 10 inch bowl will need to be left 1 inch thick to accommodate this second turning.

Make yourself a jam chuck with a tenon that will fit your chuck jaws, and extend to the bottom of the bowl. Use some sort of rubber mouse pad, or shelf liner, or piece of inner tube, and cushion the inside of the bowl and give it some grip to drive the turning. Put the bowl onto the jam chuck with tailstock support, and play with getting it to run as true as you can......it won't be true, but get it the best you can.

Then when it is the best you can get it, tighten down your tailstock live center against the tenon, and use slow speeds.......maybe 300-400 rpm, and re-true the tenon. Once that is done, place it in your chuck jaws, then proceed to true up the outside of the bowl.......once true, go to the inside and try to match a parallel shape on the inside.

You can only do this if you have left the roughout thick enough, but if you turned to final thickness, what you have is what you have.......warped bowls.

[Michael Mills]

Sounds like what happened with a couple of my daughters (they were almost 12"and warped to almost 12.5" in the oval.
What we did was mount them on the lathe (lathe off) and use an angle grinder with a sanding disc to get them where they could rotate the full 360*.
You will be taking wood off of the two oversized sides.
You can then retrue your recess or tenon.

[Doug Ladendorf]

Doesn't the head turn on that lathe? Turn it out 45degrees to clean up the outside.

[Roger Chandler]

Sounds like what happened with a couple of my daughters (they were almost 12"and warped to almost 12.5" in the oval.
What we did was mount them on the lathe (lathe off) and use an angle grinder with a sanding disc to get them where they could rotate the full 360*.
You will be taking wood off of the two oversized sides.
You can then retrue your recess or tenon.
In my opinion, the tenon should be trued up before ever attempting the truing of the bowl itself.....totally can eliminate any use of an angle grinder.....which is pretty much outside of any normal process. :confused:

[David Delo]

What a mess Im in now!!!! I went from a 10 in lathe to a 1624 Nova to make me some bigger bowls. Well Ive got me a pile of what were about max capacity on the 16 inch Nova when I started to dry them ,that are now warped too bad to rechuck and finish turn.Any solutions?I never gave a thought to how much they were gonna warp!!


Sonny,

I thought you were asking a question about how to remount a bowl that Roger answered correctly in his first reply about using a jam chuck. After reading your post again and seeing other replies I see that might not be the case. If the bowl is just too big for the swing of the lathe I'd probably consider marking a line at the appropriate spot that will clear and cut the rim off with a jig saw, hand saw or whatever like minded tool you have.

Just in case you were actually asking how to remount a bowl, here's a couple pictures that show what Roger was explaining. This was for a vase and not a bowl but the process is the same. I usually use a vacuum chuck for my bowls so I don't have any pics of a bowl but like I said, process is the same. Maybe Leo has some he could post.

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Now that the tenon has been trued-up and mounted in the chuck, I'm able to finish off the machining inside and out and do whatever other processes I want to the piece.

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[Wes Ramsey]

In my opinion, the tenon should be trued up before ever attempting the truing of the bowl itself.....totally can eliminate any use of an angle grinder.....which is pretty much outside of any normal process. :confused:

I'm guessing the bowls warped to where they were wider than what would spin inside the throw. I turned a 10" bowl from a hackberry crotch that is now over 11" OD one way and about 9" the other. I think it will make a nice platter when finished :eek: If it had started closer to 12" I'd be grinding away the sides trying to get it mounted.

[Aaron Craven]

I just rough turned a number of oak pieces that were close to what my lathe could handle... Now I'm wondering if I'll be able to re-mount them when the time comes... hurray for heartburn! :D

[Bob Bouis]

Depending on how it's warped you might be able to tilt it one way or another between centers.

[Robert Henrickson]

I use a rasp intended for horses' hooves to make 'adjustments' like this.

[Roger Chandler]

I just rough turned a number of oak pieces that were close to what my lathe could handle... Now I'm wondering if I'll be able to re-mount them when the time comes... hurray for heartburn! :DSounds like a perfectly good opportunity to tell SWMBO THAT YOU REALLY DO NEED A NEW AND LARGER LATHE! :D
Good luck with that! ;)

[Aaron Craven]

Sounds like a perfectly good opportunity to tell SWMBO THAT YOU REALLY DO NEED A NEW AND LARGER LATHE! :D
Good luck with that! ;)

Haha! Think that'll work?

[Dwight Rutherford]

If your bowl shape follows a continuous curve from bottom to lip, you can cut the lip back on a bandsaw. This will result in a somewhat shallower bowl with a smaller diameter but will clear the ways of your lathe allowing re-turning.
If your bowl shape has straight sides, then the previous suggestions can work.

[William Bachtel]

Be careful on that bandsaw.

[Sonny Kemp]

Sorry for the slow response fellas, Ive been at work.Yes the swing of the lathe is not big enough to let it turn over the ways,therefore I cant true up my recess to chuck it to return.My headstock does swivel but I cant bring up my tailstock then to hold it to true the tenon.Its about 17 1/2 in and my lathe is 16,Im not sure theres gonna be enough left to come round even if I do get it where I can turn it.Probably all I can do is try to cut the rim down and take whats left.They are contoured toward the bottom.

[Brice Rogers]

Sonny,

Since you don't have a lot to lose, let me offer another alternative. If you have enough thickness, you could take a slice out of the bowl and glue in a strip of contrasting wood. Or you could take multiple slices out of the bowl and re-glue in other pieces. Just take out enough that your bowl ends up at roughly 14-1/2". (I'm guessing that if your 16" bowl warped to 17-1/2" in one dimension that it is 14-1/2 in the other.

By putting in a contrasting color, it might look like you planned it that way. I've seen some bowls that have a wide strip with a narrow strip on either side. I thought that it looked pretty neat.

After you cut the bowl, you can flatten the cut by carefully pulling it across a full sheet of sandpaper that is glued to something very flat. Of course there are other ways, but I don't know what you have in your shop.

[Ben Darrah]

If you have a router, 7 degree dovetail bit, and guide bearing, you can cut a perfect circle template smaller than the existing tenon and sized for your chuck jaws. Screw it to the old tenon, then cut a new round tenon into it. Now return the bowl with the headstock at 15, 45, or 90 degrees. This is how I did it w/my 1645.

[Ben Darrah]

It will work with recesses too. Just cut the template with a perfectly circular hole and double side tape it.

[Sonny Kemp]

Ben are you saying just cut a circle for the template sized for the router bit to cut the diameter of my chuck jaws and put that over my existing recess in center of it and cut my recess deeper than the existing out of round recess?

[Jamie Straw]

Sorry for the slow response fellas, Ive been at work.Yes the swing of the lathe is not big enough to let it turn over the ways,therefore I cant true up my recess to chuck it to return.My headstock does swivel but I cant bring up my tailstock then to hold it to true the tenon.Its about 17 1/2 in and my lathe is 16,Im not sure theres gonna be enough left to come round even if I do get it where I can turn it.Probably all I can do is try to cut the rim down and take whats left.They are contoured toward the bottom.

Do you know anyone who has a bigger lathe? I turned a bowl that fit my lathe, but when I needed to finish the foot, it wouldn't fit in my mini-Cole jaws, so I went looking for someone who had a set of normal-size Cole jaws.

[Bob Bouis]

You're welcome to drive down to Jackson, MS, and square them up on my lathe with its 20" swing. Kind of a long way, though.

[Brice Rogers]

I guess a big question here is how thick are the walls of the bowl?

If I did my math right (not guaranteed), if it started out at 16 inches and now ranges from 17-1/2 inches to 14-1/2 inches (?), you're going to need a wall thickness of at least 1.75 inches in order to end up with only a 1/4 inch wall thickness when you finish it round - - if you turn it outboard.

[Sonny Kemp]

Thanks everybody.After suggestions and a nights sleep and much thinking why don't I just flatten the bottom on my disc or belt sander and screw my face plate to it and tru up the outside after turning the headstock 45 degrees? The bottom is plenty thick.

[Ben Darrah]

Ben are you saying just cut a circle for the template sized for the router bit to cut the diameter of my chuck jaws and put that over my existing recess in center of it and cut my recess deeper than the existing out of round recess?

Yes, you just need to enlarge the recess just enough on the sides and bottom to make it true again. The closer you can keep the recess to the closed jaw diameter, the better it will hold.

[Jamie Straw]

What a mess Im in now!!!! I went from a 10 in lathe to a 1624 Nova to make me some bigger bowls. Well Ive got me a pile of what were about max capacity on the 16 inch Nova when I started to dry them ,that are now warped too bad to rechuck and finish turn.Any solutions?I never gave a thought to how much they were gonna warp!!
So I guess one of the lessons is to turn to a smaller diameter than your lathe's max, eh?:D I'm wondering about how the bowl was laid out on the blank. If the rim of the bowl was on the pith side of the blank, I believe you're likely to get much higher "peaks" during drying/warping than if your tenon is oriented toward the pith.