DOC of 0.25" on 2.5" diameter? What Haas machine are you using? I don't think either of mine have the low speed torque to drive a cut like this at around 400 fpm with a feed of around 0.01 ipr; which can give a really nice finish on 1018.
My experience with 1018 is that it needs negative rake tooling, a DOC of at least 0.50" and maybe more, and a good healthy feed in the 0.01 to 0.015 ipr. This can give nice tight broken chips and a very good surface finish. Unfortunately on small diameter material you can get serious deflection and poor size holding.
When you go to finishing cuts to get good sizes it can be awkward because then you have to go to positive rake tools, lots of rich coolant and shallow DOC so you are just peeling of a tiny sliver at a slow feed.