Many You Tube videos on how to use the bubble gauges as above.
I have been using mine for 50 years.They do the job just like the wis-bang computer/digital $$$$$$$ machines.
That Alemite set is down right cool ! What ever you get it for the turn tables are worth it.
Would be nice if the owner knows how to use it.Maybe he has a book to go with it.That would make it priceless.
Agree. It is missing the dial lens on one side but I'm thinking the turn plates would cover the cost and just for giggles I might be able to reproduce the lens