Patent ID: 9604298
Date: 2017-03-28
CPC Classifications: B23B,B23G

Claim:
1. A method of manufacturing a work having a screw thread, comprising: removing an apex of a ridge in an incomplete thread part helically formed in the work by screw thread cutting, by a tool equipped with a cutting blade by: forming first helical cutting mark at the apex of the incomplete thread part, and forming additional helical cutting marks positionally displaced relative to the first helical cutting mark, wherein in a state where the tool is located so that the cutting blade cuts into the apex of the incomplete thread part in a width smaller than a thread pitch and the work is rotated around a thread axis that is a center line of the work, the cutting blade of the tool is moved in a direction resulting from combining a movement in a direction of the thread pitch and a movement in a direction of height of the incomplete thread part to allow the cutting blade of the tool to cut the apex through a linear relative movement along the apex helically formed in the incomplete thread part from a starting position to an ending position of the incomplete thread part or from the ending position to the starting position, so that one round of cutting for the apex of the incomplete thread part leaves the first helical cutting mark, the one round of cutting helically is repeated plural times to form the additional helical cutting marks with the cutting blade of the tool being positionally displaced relative to the incomplete thread part in at least the direction of the thread pitch toward the ending position side or the starting position side of the work, and the apex of the incomplete thread part is accordingly removed so that a plurality of the helical cutting marks are adjacent to one another in parallel and continuous in the direction of the thread pitch.