I'm an amateur garage hack with a 1hp mill that normally just plays with aluminum. Well, now I find myself with a project to machine some parts that are made out of 8620 steel that is case hardened. I've never cut steel before, much less a hardened steel like this.
I have a 1/4" carbide 4 flute end mill that I plan to use for this task. The depth of cut is about 1/2" and I plant to cut from just one side using conventional cut rotation with about 0.030 per pass. I don't have coolant, so it will be dry cutting. According to the Whitney Tool Company Speeds and Feeds Calculator online with a suggested 100 surface feet per minute and 0.002 chip load per tooth, I should be running my mill at about 1528 rpm and use 12.22 inches per minute feed rate.
Does this seem reasonable at all? I thought that seems pretty fast and aggressive for my little mill. I'm okay going slower, but I also have heard that too slow or not aggressive enough can be bad for carbide end mills. Any advice for a steel newbie would be greatly appreciated.
Thanks in advance!
JJ