Like most wood turners, I have made my share of bowls. Thin walled, thick walled, and any diameter from 3″ to 15″. Initially I used my disc sander to reverse the bowl, pressed onto the disc by the tail stock, and then clean up the foot. Works perfectly fine for chunky bowls, but it does tend to put a lot of stress on thin walled bowls, and it distorts them quite a bit.
When I thought about how to improve this, I realized that the problem was the transfer of friction. In order to generate the friction, pressure is required. If the two points on the bowl between which the pressure is applied, sit at opposite ends, i.e. in the centre of the foot and at the rim, then the entire bowl has to handle the pressure.
However, if the pressure was transmitted straight through the material to the bottom of the bowl, then almost the entire bowl is without any stress at all. So here’s the solution:
This is a piece of 3″ by 3″ pine, very cheap. It’s about 4″ long, but obviously you can make it as long or short as you want. The back end is simply turned into a stub that will fit one set of my jaws. Make sure you either have a shoulder or the backside is perfectly perpendicular, to ensure a good seat in the jaws.
The front side is turned into the approximate shape of the smallest bowl you intend to use it for. Cover with double sided tape and put some kitchen non-slip rubber mat on top. Done.
Now, when you mount a bowl onto this and apply pressure with the tailstock, the vast majority of the bowl is not under stress, and only the very bottom of the bowl has to carry the pressure onto the chuck.