How to get better surface finish with 2” face mill

Here is what I was running:

Workpiece: 1018 Hotroll DOC: .010 then .015. Both finishes looked shitty IMP RPM: 1100 Feed: about 2 ipm.

I didn’t look anything up but I believe my setup was rigid. Every axis locked except X. Spindle was only sticking out of the mill about an inch. Etc

Was I in the ballpark? What can I do to improve my next pass?

Thanks