so far all I've been cutting on the mini mill is aluminum (I made the belt drive conversion kit) I've got some steel I want to mill down, but honestly, I'm nervous.... I have two end mills that I've been using. 1/2" 2 flute I've been mainly using that was brand new, and a 1/4" 4 flute I had in the tool box I bought that was still sharp. (And a few smaller ones that are still sharp too). What are you guys using to mill (mild) steel? What's your usual doc? I'm afraid to ruin an end mill. Not because they cost money, but really, because they're a pain for me to get... but I'm not opposed to getting a couple more more suited to steel over aluminum tho. I know I need to get a roughing end mill, but I'm really looking for guidance here to get into machining steel... I know, now that I've broken in the mill somewhat, I need to readjust and tighten. It vibrates/chatters a bit when cutting.