Neck portion grinding apparatus and grinding device employed in the neck portion grinding apparatus

A neck portion grinding apparatus comprising:

• a grinding device having a disc-like grinding wheel and a wheel rotating device for rotating the grinding wheel;
• and
• a machine tool having a main shaft for rotatably supporting a rotating tool and a table for mounting the grinding device or a workpiece to be processed by the rotating tool thereon, and relatively moving the main shaft and the table by numeral control,
• wherein the grinding device is adapted to be detachable with respect to the machine tool,
• wherein a shape of a neck portion of the rotating tool can be changed by relatively moving the main shaft and the table in a manner to approach with one another while mutually rotating the rotating tool and the grinding wheel, and grinding the rotating tool by the grinding wheel, and
• wherein the workpiece is processed by the rotating tool when the workpiece is mounted on the table and the main shaft is moved in a direction to approach to the table.