Re-turning - best strategy?

[Paul Heely]

Edit: Just read Mike's post above, which basically says the same thing as I say below.....

if you have large enough jaws you might try turning a recess on the inside of the bowl to hold it while you true up the recess on the bottom of the bowl. I saw Ashely Harwood do something similar in her bowl turning video. The process would look something like this:
1. Use the existing out of round recess and the tailstock to mount the bowl with the foot of the bowl at the headstock end of the lathe. Basically a jam chuck using the chuck inside the untrue recess.
2. Turn a recess on the inside of the bowl.
3. Reverse the bowl and hold it on the recess you just turned on the inside of the bowl. True up the recess on the foot of the bowl.

I've done this many times when I was messing around with the push cut cut stuff, and it works well to hold the bowl. Only catch is it requires a good size set of jaws to hold the bowl by a recess on the inside. I'm lucky enough to have a full set of dovetail jaws for my VM120 chucks.

Paul

[Neil Strong]

I put a recess in the inside bottom of bowls at the green turning stage. I have sets of spring dividers that are set to the diameters that will shrink to the sizes of my long nosed jaw sets (2", 4" & 5") when seasoned.

I make a slightly deeper internal recess in woods that have larger radial to axial shrinkage to ensure I get four contact points when I re-chuck.

For very deep bowls I use a 4" or 6" extension adaptor to position the chuck and rim of the bowl further away from the headstock.

Final turning step 1: I complete the turning of the outside of the bowl with a recessed in the foot that is proportional to the size of the bowl and then complete by polishing the outside of the bowl.

Final turning step 2: I remount using the outside bottom foot recess to turn the inside of the bowl and then polish.

Bowl done!

Some like to go back and turn off the outside bottom of their bowl. I like the bottom of my bowls to have a well defined foot, which I complete with Final turning step 1.

I turn all of my bowls outboard and never use the tailstock (unless spindle turning).

As seen in the above video link, RR prefers to clamp onto the foot of his bowls when doing the final turning of the insides, for which he mostly uses multi-step jaws but not in that video. I prefer to hold by expanding into the completed recess in the foot.

One of the disadvantages of my method is that I need to have many jaw sizes (and dedicated chucks :~) to get the right proportions to match the different bowl sizes, whereas Richard only needs the multi-step jaws and one chuck for that.

On the survival rate of these two holding methods, RR's is better but I have seen him lose a few off the chuck! I probably lose a few more due to the occasional inside cut that is too heavy, which can pull the piece out of the recess. But that doesn't happen very often and I've lost count (somewhere after the first thousand) of how many bowls I've successfully made that way.

Worth a try if you haven't already.