Bridgeport Mill Question
I'm looking at a used Bridgeport mill and I noticed it does not have chromed ways (the fancy swirls). Was this an aftermarket upgrade or are they just worn out? What do they do for you?
My BPT machines came factory equipped with chrome ways. One is a "low end" CNC called the Extrak and the other is a "low end" VMC called the V2XT - both are based on the classic 2hp or so Bridgeport mill.
If yours had chrome ways (I dunno if it was standard or an option on early machines) and the chrome is gone, it might make a very good drill press but you might be leary of it being a candidate for a precision mill due to severe wear.
I'd be inclined to seek out better if you're looking for a CNC retrofit candidate, especially if the chrome is worn away. You can't expect software to make up for tired/severly worn iron.
HOWEVER, I have an Excello that has ground and lapped and UN-chromed ways. With well adjusted gibbs, it holds tremendous accuracy even though there are some wear/score marks from prior use/service. IT does get snug when you get out of the central use path with snug ways but it still does a fine job.
BTW, it is for sale (w/DRO) in case someone is looking for a good manual mill in otherwise very good condition....
Sorry for shameless thread hijack but the urge struck....
EDIT: iron bed running on chrome ways, less wear and friction potential, w or w/o way lube.
Iron against iron, OK wear but potentially more friction w/o way lube. IT will be less friction w/way lube but not as low as iron+chrome
Neither of my bports came with Chrome ways, and my dad bought them both new. The old timers were kind of leery of it because a normal non chrome machine could be easily re-scraped good or better than new, not so of the chromed ways. Plus they cost a LOT more with it :-)
The "fancy swirls" are not an indication of chromed ways. This is a process added when the ways are "scraped" to insure they are flat and true, (an art in itself). The swirils you see are actually added during this process so as to retain lubrication of the sliding members.
The swirils can be found on chromed and non-chromed bed ways.
If the swirils are missing in certain areas and present in others, you can be assured that the machinehas been well used or abused!