Now that I have established the tenon I work on the curve of the bowl, it is a very shallow curve and you can play with it if you want, you can make it almost flat or a fair bit steeper, in this picture it is not really looking curved at all, but it is, that is just the camera playing tricks.
you also want to think about where the edge of the bowl will end up, this particular piece of wood has a bunch of inclusions in it, so getting four perfect corners is maybe going to be a stretch, but with experience you can find a good spot for the edge to be. Even if you have to take the tenon down a bit to make the curve how you want it.
I'm fairly happy with that, and I sand the bottom of the bowl with the power sander but not the corners, if you do you can catch an edge and or make the edge of the corner rounded over too much, so I only power sand if I need to, I find that I can usually hand sand just fine.
Remember to go in the direction of the grain.
Not always but sometimes just for fun I put a little surprise on the bottom of the bowl.
At this point I finish the bottom of the bowl, in this case I put a coat of sanding sealer on the bowl, I'll finish it up with lacquer off the lathe.
Now I've changed chucks, I have my regular jaws on this chuck, of course if you don't have two chucks then you have to swap the jaws from the pin jaws to these regular jaws. I put the plastic insert into the jaws and place the tenon into the insert, bot only tighten lightly.
Again I use the cone on my live center to make sure the bowl is seated correctly in the insert in the chuck.
Now I tighten down on the bowl, but don't over do it!
Sometimes for whatever reason the center of your hole may not line up with the live center tip, this can cause the bowl to vibrate when turnings, which is no fun, one way to remove this problem is to remove the tip of your live center....
With the tip removed the live center then uses the ring to press on the bowl to support the turning, remember that plastic insert is not nearly a strong an attachment as the metal chuck jaws, you you have to go carefully.
With the live center supporting the bowl again move your tool rest up nice and close as you will be turning air again.
I first cut down to the edge of the bowl so I have a complete circle this allows me to visualize the shape of the bowl.
Basically you want the top edge to be parallel with the bottom edge along the curve, as you can see in this picture it is NOT parallel, the middle part is much fatter than the corners are, I'll fix that in the next pictures.
The pessimist complains about the wind; the optimist expects it to change; the realist adjusts the sails.
William Arthur Ward