PROBLEM TO BE SOLVED: To provide an unequal lead end mill capable of preventing regrinding of a blade groove by mistaking as the other blade groove different in a torsion angle, by easily discriminating a difference in the torsion angle even in a visual inspection, when regrinding the unequal lead end mill.;SOLUTION: The unequal lead end mill is provided by forming a plurality of cutting edges 5a, 5b, 5c and 5d different in a torsion angle on the tip part outer periphery of an end mill body, and the blade length or the groove length of the cutting edges 5a, 5b, 5c and 5d or the blade grooves 4a, 4b, 4c and 4d is different in response to a difference in the torsion angle, and the cutting edges 5a, 5b, 5c and 5d or the blade grooves 4a, 4b, 4c and 4d of the same torsion angle or lead are formed in the same length.;COPYRIGHT: (C)2015,JPO&INPIT
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