How do you guys hold a bowl blank to cut it with a chainsaw?

I posted my cutting stand before but it really works well. Keeps my back and works great for trimming half logs as well as whole round sections

This is what I do to hold them to trim the corners off.  Very quick and holds super well.
A $12 bench holdfast works just a well, I already had a fancy one.

Generally, I will put the log blank up on another log stood up end grain wise, and chock a couple of cut offs on either side to keep it from rolling. I use a level to mark a plumb line through the center, or to either side, and have a number of plywood strips in various widths to mark off how thick of a blank I want (no measuring). If I am going to cut off the corners, I make sure to cut off the bottom outside part of the bowl blank before cutting down the center. Mostly this gives a flat spot on the bottom of the blank for it to sit on so you can mark a circle, and then trim off the corners. With the flat spot, it will not rock and roll when trimming. When trimming the corners, start cutting on the left side, so the teeth on the side of your chainsaw can dig into the log and hold it still. If you cut going to the right side, the log will want to spin into the saw. If you have a really big piece, and are going to cut several blanks out of each side of the pith, cut about 90% or the way through, then roll it half way around and cut the rest of the way through.

robo hippy