[Railgun]

Hogging mills come in two, four and more flutes depending on the sizes. More flutes increases the feed rate since you've got more flutes sharing the load. But of course you again need the power to push them that hard. The whole hogging mill deal is really a big production sort of choice. Hobbyists just don't need that sort of thing.

The choice of two or four/more flute use is still based on if you're cutting a slot or not. Two flute cutters are center cutting types so you can plunge cut a slot. Or even if the slot is open ended it's still good to use a two flute for them.