I have this old metal lathe. It's B.F Barnes and is at least 100 years old. It has that patina that a lot of old iron gets. Some folks think this patina should not be disturbed. Other folks think the tool should be made to look as close as possible to the original factory finish. For this lathe I am of the mind that the patina should be removed. I want customers to see what was possible 100 years ago. I want the machine to appear new, or nearly new, the way it would have looked in a factory where the machine was wiped down and cleaned every night. So, opinions? Thanks, Eric
Go for it and make it look the way you like personally, it is just an old little lathe. It is not a ancient Egyptian mummy.
If you ever want to revert back to that "patina", you can always leave it outside for 3 weeks and slop some dirty oil on it (I can supply that) and then add some dust on top of that oil for authenticity.
The lathe is now and will be fully functional. I will be making parts on it. These parts will be just for my own enjoyment, not for paying customers. The bed ways look as if they were made on a planer or a shaper. Even under the headstock there are no scraping marks. I am not sure how straight or worn the ways are but I can still see longitudinal marks that run the length of both the carriage and tailstock ways. Eric
If the lathe is yours, you should do whatever you damned well please to it.
If you're trying to maximize its value when you get too old for it or pass away, then you're guessing at what the fashion will be in antique machinery in the (hopefully distant) future, and that's not a useful occupation in my opinion.
If it were mine I'd do whatever is best for it as a piece of working machinery, and let my heirs decide what to do with it after I no longer care.
Some lathes were left just as the planer left them, but most from 100 years ago were scraped. Much later, they were often planed or ground and then "frosted" with a scraping tool, mostly for appearance but ostensibly to hold oil.
Longitudinal marks can be wear from grit, or maybe evidence of the original planing.
The first thing I'd do is to lay a precision straight edge on the ways
-- the bevelled-edge type, if you have it -- and put a light behind the straight edge. See how much "dip" there is from the front of the spindle nose to the next 18" or so towards the tailstock end.
If there's a lot, just clean it up and use it as-is. If it's less than
0.001, it's worth considering running an Arkansas stone along the bed to knock down any burrs. If you don't have a good stone, you can use a really flat block of metal with some 600-grit wet/dry wrapped around it.
This will horrify the purists, but it isn't going to make anything worse on a 100-year-old lathe with a lot of "patina."
Getting the patina off is possible, but it depends. I'd start with phosphoric acid (Naval Jelly) and coarse steel wool. But that stuff is problematic on cast iron. Sometimes it leaves a layer of black oxide that's really tenacious.
It may require hydrochloric (muriatic). If you use that -- outdoors -- I hope you're aware of the dangers. I haven't used it on cast iron but I'm told that you really have to neutralize it carefully with baking soda or washing soda, because of the surface porosity of gray iron.
On steel, it leaves a silvery but frosty finish. I think it's the same on cast iron.
Greetings Ed, The ways are remarkably flat and straight. The marks that look like artifacts from planing are too regular to be waer marks. Especially since the same marks are under the headstock. Any patina removal will be done with oil and steel wool or something similar. I have decided that since this machine is for my enjoyment and is not something that only one exists of I will be making it look as close to the original factory finish as possible. The thing was originally painted black on the cast surfaces but I don't know if it was Japanning. I can buy the stuff but it needs to be baked and costs way too much. Some nice black lead based paint would probably be good too but there is no way I can find any of that. Eric