Machine tool with bore diameter measuring apparatus and tool position compensating apparatus

A machine tool for operation on a workpiece formed with a bore to be machined comprising:

• a machine body;
• a work table mounted on said machine body for mounting thereon said workpiece formed with a bore to be machined;
• a spindle head mounted on said machine body;
• a tool spindle rotatably supported in said spindle head;
• a motor drivingly connected to said tool spindle for rotating said tool spindle;
• a servomotor for effecting relative movement between said work table and said tool spindle;
• feed control means connected to said servomotor for controlling said servomotor in accordance with feed pulses and axis designation signals;
• a tool holder receivable in said tool spindle;
• a boring tool supported on said tool holder;
• means provided in said tool holder for adjusting the radial position of said boring tool by utilizing rotation of said tool spindle;
• a contact detecting head with a predetermined diameter secured to said tool holder in co-axial relationship therewith;
• means electrically connected to said contact detecting head for detecting contact between said workpiece and said contact detecting head;
• bore diameter measuring means connected between said contact detecting means and said feed control means for applying feed pulses and axis designation signals to said feed control means so as to move said tool spindle relative to said workpiece from a first position to a second position wherein at each of said first and second positions said contact detecting head contacts said workpiece, along a path passing through the center of said workpiece bore, to thereby measure the diameter of said workpiece bore;
• and
• a motor control circuit connected to said motor for controlling said motor;
• said motor control circuit being responsive to said measuring means for rotating said tool spindle to adjust the radial position of said boring tool.