I have the need to make some rectangular holes with good precision between 3-4mm. I have a G0704 and do not want to broach or file the hole. I see there are end mills made for making a square hole after pre-drilling. If I use a center cutting helix square end mill like https://www.mscdirect.com/product/details/78598356, will I be fine with a fixed chuck/arbor or do I need one that gives in a circular motion? My apologies if I'm not using the right terminology but most of the videos I see have a rotating motion on not just the end mill. I also saw something that said the number of flutes should be 1 less than the corners you're trying to cut. Would I still be able to do square corners with a 4 flute end mill?