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Discussion Starter #1
Another newbie turner question:
I've roughed out some bowls from green/ wet wood and set them aside to dry. As expected they are now nice ovals. Even the tenon is oval.
What is the best practice to reshape back to round? Inside first? Outside first? Will the no longer round tenon be an issue.
Thanks
 

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The oval tenon will be an issue. I use my chuck with jaws closed and a piece of leather to pad them and place the hollow on it. Bring up the tailstock with a flat insert to hold it. Reshape the outside, including the tenon, the chuck like normal to redo the inside.
 

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Sawdustfactory's method will work.

I have also seen people using a dough-nut chuck to mount for re-shaping the tenon.

A doughnut chuck is also used by some folks for removing the tenon or if the wall thickness is too thin to allow reshaping.

Forum member John Lucas has a good article on different methods to reverse mount a bowl.

http://www.docstoc.com/docs/36688745/Methods-and-Jigs-for-Reverse-Turning-Bowls
 

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Thank you both.
I have some leather scraps I've been saving. Now I know why. And that link was very helpful. I now have options I understand and I may try and make a few different options that were listed.
 

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My way of doing the second turning ...

1) Like sawdustfactory, put the piece over some kind of lump that will act as a friction drive, and bring the tailstock up getting the point into the dimple that was there from the first turning.

2) Reshape the tenon and the shoulder (which the rim of the chuck presses against) -- in my case, the tenon needs to be a dovetail to match the chuck jaws I use.

3) Flip the piece around and put the tenon in the chuck

4) Position the tool rest at 90 degrees to the lathe bed (i.e. across the top of the bowl) and with a pencil draw the outermost circle that fits on the rim, just touching the outside at its narrowest point; now draw the innermost circle that fits on the rim, just touching the inner edge at its widest point.

5) This shows me the thickest I can make the walls of the bowl when I turn away the bulge. Hopefully there's enough wall thickness left ... otherwise I've got a problem.

6) Now I turn the outside of the bowl (best to begin the cut at the foot and work towards the rim, it's the direction where each fiber is supported by the one ahead of the cut)

7) Sand the outside

8) True the rim

9) Turn the inside of the bowl, starting at the rim and working towards the base (again, because the fibers are supported throughout the cut in this direction) but just the first inch or so

10) Sand the first inch

11) Work down another inch inside the bowl

12) Sand it, blending into the part that was already done

Repeat these steps till I reach the bottom of the bowl

13) Flip the bowl around one last time (I hope) and use either a jam chuck (as in, a plate with a groove for the rim of the bowl to seat in) or a friction drive (a lump of something with a piece of leather or similar); bring the tailstock up but not too tight (or it will punch through the bottom of the bowl ... DAMHIKT)

14) Very carefully turn the foot of the bowl, leaving a little nubbin in the middle where the tailstock is

15) Sand it

16) Take it off the lathe and with a sharp chisel (or a flush-trim saw) remove the nubbin and sand by hand.

This works for me -- feel free to take as much as helps!
 

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Discussion Starter #6
Thanks Duncsuss,
That was very helpful also. I notice frequently that getting answers leads to more questions.

1) there is no dimple in my tenon as I haven't been using the tail stock in the first turning, just the chuck. I will try changing that but for now will just try to center the point as best I can.

2) why do you sand one inch at a time?
3) what do you use to sand the inside of the bowl with. This has been enough of a challenge for me the it may be worthy of its own thread.

BTW I love the idea of marking the wall with the pencil. Big thanks for that tip.
 

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Thanks Duncsuss,
That was very helpful also. I notice frequently that getting answers leads to more questions.
Funny how that happens ... :laughing:
1) there is no dimple in my tenon as I haven't been using the tail stock in the first turning, just the chuck. I will try changing that but for now will just try to center the point as best I can.
Do you have a "center finder"? If not, just draw a couple of straight lines, e.g. one on the longest axis and one on the shortest axis. Use a center punch or spike to make a dimple as close to center as you can eyeball it.

After I'd done this a few times I realized it would have been much easier to simply ram the bottom with the tailstock before setting it aside to dry.
2) why do you sand one inch at a time?
It's not just sanding, it's the whole "thin the wall then sand it" process.

The thinner the wall is, the more likely it is to flex as it's turning. This leads to chatter and tool marks that you simply can't turn or sand away (because it's still flexing as you sand it).

By thinning the walls inch at a time, you get better stability in the area where you're cutting.
3) what do you use to sand the inside of the bowl with. This has been enough of a challenge for me the it may be worthy of its own thread.
The same sandpaper I use for the outside. If I did a decent job with the tools, I'll start at maybe 120 or 150 grit.

Having a reversable lathe is an advantage. Sand in one direction, then in the other -- it helps get rid of the rough spots which always seem to develop just as the side-grain turns into end-grain (i.e. there are 2 patches, 180 degrees apart.)

BTW I love the idea of marking the wall with the pencil. Big thanks for that tip.
Not my idea -- just passing it along :thumbsup:
 

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What the others said.
Turn one of these with scrap in case you do forget and remove the center dimple (drill for the 16p nail while on the lathe).
You can use it find your center with your chuck before you set it back to dry if you turned the first dimple off.
Also used to center a faceplate.
Or you can buy one for about $20. :no:
 

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Discussion Starter #9
Thanks NC,
I won't buy one. I did se them today in woodcraft for $12. But not the right size ;)
 
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