If you are getting a horrible finish my guess is that your material is annealed or normalized. A lot of medium or high alloy steels like all the 41xx series are crappy to machine when they are soft.
What speeds/feeds have you been trying. I would try at 400FPM with a feed of 0.01" per rev and a DOC of no less than 0.05. No coolant, just an air blast. You need to find a sweet spot where the chips are peeling off blue.