Getting any older? piece of machinery restored, wether its in our
trade or engineering in general, involves pretty much the same number
of steps from start to finish.
So in your case, a rolling mill,
needs to be dismantled
Each part then needs to be cleaned up, washed off with the
equivalent of kerosene or white spirit, a more volatile HYcarbon.
then you will see what is causing it to not run smoothly. You may
need to find someone who uses one regularly near you to check it
Then rolls need to be checked for truth, ie no deep rust spots or
other surface iregulateries,
carefully reassembled and lubicated as follows.
the roll bearings are best oiled with any 40 weight car engine
the gears are best greased with any lithium grease gun grease, as
you wont be able to get to them when the covers are on.
Then give it a try. Then see if the grittyness? is still there.
Depends on its history.
It also depends on wether its a pro mill or just a hobby small set.
What size are they? roll width and dia? any serial no ? to try and
date its year of mfg?