HEAD REPLACEMENT-TYPE CUTTING TOOL

摘要

The holder (1) is provided at the attachment hole (4) with the fitting part (4B) formed in a tapered shape, and the leading end face (2B) is perpendicular to the central axis (O). The attachment part (12) formed in a tapered shape protrudes on the cutting head (10) from the rear end face (11C) perpendicular to the central axis (O) of the cutting part (11). The cutting head (10) is attached to the holder (1) in such a manner that the attachment part (12) is fitted into the fitting part (4B) by screwing the female thread part (3E) with the male thread part (13) and the leading end face (2B) is in contact with the rear end face (11C). The inner diameter to outer diameter ratio d/D1 which is a ratio of the inner diameter d of the fitting part (4B) before being fitted in relation to the outer diameter D1 of the leading end part of the holder (1) is from 0.5 to 0.8. The outer diameter expansion percentage (D2 - D1)/D1 x 100 (%) formed by D2 - D1 which is a difference between the outer diameter D2 of the leading end part of the holder (1) after being fitted and the outer diameter D1 with respect to the outer diameter D1 is in a range of 0.022 x d/D1 - 0.003(%) to 0.33 x d/D1 - 0.06 (%).