End mills come in hundreds of sizes and styles. 2 flute,4 flute,ball end, single end, double end, left hand cut,right hand cut, reverse spiral, roughers...and the list goes on. The 4 flutes will not plunge cut unless they are the center cutting type. I would not recommend using an end mill in a drill press. The cutting action of an end mill in a drill press will be very much different than a twist drill. The margins of a twist drill keep the drill from wandering while drilling. An end mill is designed to cut on the sides and will wander badly when plunging on the light (long) spindle of a drill press causing serious chatter.Damage to the spindle and possibly the operator may occur depending on the setup.