This is not an uncommon problem, especially on older Windmills with
wear on the cylinder bushings. The next time you run the press, keep
the rollers off the cylinder and turn the press over by hand (drop the
clutch and turn the flywheel until the cylinder has turned halfway.
There you should find oil, generally at the edge of the cylinder.
Clean it off and it will not return until the press has sat overnight.
If oil is getting on the cylinder quicker than that, expecially while
you are running, then you certainly need to invest in new bushings for
the cylinder (ie: call the mechanic -- (: < p)).
(with a 1952 Windmill in the shop).