| 摘要 |
PROBLEM TO BE SOLVED: To provide a cutting instrument and a method related to the instrument.SOLUTION: Diameter of a reverse direction cutting blade can be adjusted to any one of plural kinds of diameter setting, and holes of various diameters can be formed using a same instrument. During cutting operation, a user does not have to concern about proper diameter, and limit diameter can be set in advance so that the cutting blade can be easily disposed until reaching the preset limit. Similar to an instrument in which, a user can give sight and/or tactile feedback for confirming desired positioning of the cutting blade, the cutting instrument, in which, the reverse direction cutting blade is separated from a front boring chip and is protected in a cavity formed in a body of the instrument when the cutting blade is not used, is disclosed. |
