Just an FYI:

The crescent shaped marks on the way surfaces are standard on a new
Bridgeport (and many other machines as well) but are not necessary
according to many. The sliding surfaces are first precision scraped
using a method which leaves very little distinctive markings. After
the surface is as close as you need it, some apply a oil holding
pattern composed of marks (not always crescent shaped).
The idea here is to let people know that not seeing the usual pattern
on a way surface is not conclusive evidence of wear especially if the
machine has been rebuilt previously.

dennis in nca

On Aug. 1 Richard says:

You can always see the crescent-moon scraping marks, testifying to the
original precision surface, at the ends, but depending on the degree of

wear, these marks are more or less worn off towards the middle. On
this
particular machine, the photo shows they are completely obliterated
except at the very ends of the ways, indicating extreme wear, concave
where it should be flat.