2pcs/lot R0.25*D6*30.5*75L*2F HRC55 Tungsten solid carbide Coated Tapered Taper Ball Nose End Mill cone type cnc milling cutter 1pcs r0 75 d6 30 5 75l 2f solid carbide 6mm ball nose tapered end mills router bits cnc taper wood metal milling cutter