I don't know George, you're a much braver man than I am working on those whirring propellers like those.... I had a small catch on a regular round bowl the other day, the scraper handle kicked up towards my face and I dodged, my hand slipped and caught a finger between the edge of the bowl and the tool rest (I think -- I was busy dodging the tool handled to see where my finger got smacked...)... no damage, just a bruise, but still smarts.... I know I'd wind up with at least one finger in that propeller....
great looking bowls you got there... and even though I know I'll get smacked, need to try one.