Milling tool is a kind of tool for milling the fishes. Such as bits, cone, cutter gauge, slip elements, swivel wash pipes, subs, parts of deep-well pump, etc. 

The flat bottom and concave junk mill milling the fishes with the effect of drilling pressure by the YD alloy and anti-abrasive material on its bottom surface. The junk was carried out of well by the drilling fluid.