re: Marking Gauge

Nice build 'dog... that ruler looks like a very useful addition, often/always missing from most bought ones ('cept the 'peckrs).
Like the pencil addition, unless you're 1adoze that can never find one in the workshop.... and don't try to tell me it is bolted in as you're guaranteed to unbolt the next time you can't find one and the next time you use the gauge... no pencil!

Do you have a non marer (maybe an Aussie 5 cent) piece under that knurled knob to stop marking that shaft?

10¢ probably too big for yours.