THROW-AWAY TYPE DRILL

摘要

PROBLEM TO BE SOLVED: To carry out certain and smooth drilling work by preventing sudden increase of cutting resistance at the time of deflection of a tool main body and contact of a cutting blade without requiring many chips or a large chip in the case of carrying out the large diametrical drilling work on a workpiece especially. SOLUTION: Throw-away chips 17, 17 positioned on the inner peripheral side in the diametrical direction out of a plural number of the throw-away chips 17... are mounted so that their cutting blades 18 are arranged on the head end side in the axis O direction of the cutting blade 18 of the throw-away chip 17 on the outer peripheral side on a throw-away type drill constituted by mounting a plural number of the throw-away chips 17... on a head end part 15 of the roughly columnar tool main body 11 to be rotated around an axis O free to connect and disconnect as they are slipped in the diametrical direction so that rotating tracks around the axis O of their respective cutting blades 18 continue in the diametrical direction.