This faceplate ring has an internal chamfer which matches the dovetail on the 80mm C Jaws. The ring is attached to the timber with woodscrews, placed over the jaws on the chuck and the jaws opened up inside the ring to grip it firmly in place. Using a faceplate ring means that the chuck does not have to be removed from the lathe when faceplate turning.
N.B. The finish may be either silver or black due to changes in legislation regarding passive zinc plating.