The video above shows the Longworth chuck in action on the rotary axis. I have chosen to use a Longworth chuck because it can be used to mount and center candles of a wide range of diameters and can be relatively low profile. With a shorter chuck profile it's possible to carve closer to the base of the candle. The way it works is that you place the candle on the top, rotate the top plate so the fingers move in to touch the outside of the candle, then tighten down the fingers. When the fingers are tightened the rubber stoppers (white cylinder in video above) expand radially from vertical compression to hold the candle in place. Issues I am having with it are that it is very difficult to move even when none of the fingers are tightened, it doesn't do a good job of self centering the candle (likely a fit tolerance issue) and even when tightened, the rubber stoppers don't do a good job of securing the candle. I am going to live with it for now, but ultimately I will probably transition to a design that uses nails that go into the wax of the candle for a stiffer mechanical connection.