Thread gage

A method for gaging a thread portion of a threaded workpiece having a rotational axis comprises the steps of:

• a. moving a thread gage including a stylus and transducer in a direction axially of the thread portion with a tip of the stylus in engagement with the thread portion whereby the thread contour effects movement radially of the stylus tip as it is moved axially,
• b. transmitting the radial movement of the stylus tip through a linkage member rotatable about a pivot point member to a probe of the transducer, and
• c. selecting the position of the pivot point member such that a straight line between the pivot point member and a root point of a thread tooth forms an angle with a line parallel to the rotational axis of the workpiece holder which is less than the flank angle of said thread tooth at the root and such that a straight line between the pivot point member and the crest point of said tooth forms with the face of said tooth upon which the stylus tip moves toward said crest point an angle which is greater than 180.degree.-arctan
• (1/F) where F is the coefficient of friction between the stylus tip and the workpiece.

A method of profiling a thread in a workpiece which is mounted in a workpiece holder of a threading machine which includes a turret movable in directions axially of the workpiece holder comprises the steps of:

• a. mounting a thread gage including a stylus on the turret,
• b. moving the thread gage including the stylus into position to profile the thread,
• c. moving the turret in a direction axially of the workpiece holder to effect movement of the stylus over the thread surface,
• d. producing signals indicative of the positions axially of the turret during the movement of the stylus over the thread surface,
• e. transmitting the signals to a machine computer,
• f. producing signals indicative of the corresponding positions radially of the stylus during the movement of the stylus over the thread surface, and
• g. transmitting the radial position signals to the machine computer.