Abstract: A machine tool with multiple spindles and tool supports operable independently and simultaneously under independent working programs is provided with a tool support synchronizing system to produce synchronized operation of plural tool supports. Each of the working programs produces as a special synchronizing command a predetermined single character or symbol. Control circuits which control the shifting of a respective tool support in response to commands from a respective working program are synchronized with one another in response to the receipt of the special synchronizing command received from the working programs.

Abstract: A numerical control apparatus having an improved range of control functions and in which the management and use of the control program can be more easily performed. In accordance with the invention, a common data register group is provided so that reading and writing of data therefrom and thereinto can be performed by the work program side as well as by a programmable controller side.