Would you please look at the bolt knob checkering under magnification and tell me if you think the checkering was done to the bolt knob or a hole was cut through the knob and a piece that was rounded on both ends was checkered then installed into the hole?
Yes....it's a checkered plug, Michael. Hopefully the pictures will show that clearly.
What at first may appear as checkering "overruns", under close examination prove to be radial cuts for a decorative border. Obviously filed in before the plug is inserted.
As you can see from the "under side" of the knob.........the ground "facing" for the decorative radial cuts isn't quite as uniform as the top side. I presume this side was done first. <grin>
