Numerical control device including tapping pitch data group memory

A numerical control device for feeding a spindle head having a plurality of tapping tools at a most suitable speed with respect to the rotation of the tapping tools,

• said numerical control device comprising:
• a data processing section including a memory and a central processing unit for analyzing and computing numerical input data, and for performing numerical control of a machine to be controlled including rotation of a spindle on which said spindle head having a plurality of tapping tools is mounted;
• a tapping pitch data group memory for storing data representing tapping pitches of tapping tools held by a spindle head as a data group for each spindle head;
• and
• synchronous operation control means for reading, when a tool number is specified according to a machining program, a corresponding data group out of said tapping pitch data group memory, obtaining an average value of said data group thus read, and feeding said spindle with respect to rotation of said tapping tools in accordance with said average value.