Plug gage

A plug gauge comprising:

• a. a tubular body;
• b. a rod housed in said body, said rod axially movable within said tubular body;
• c. a conical element mounted on one end of said rod, coaxially thereto;
• d. said tubular body formed with at least two guide channels, said guide channels transverse to the longitudinal axis of said tubular body;
• e. a radially movable feeler ball housed in each of said guide channels, said feeler balls resting against the side surface of said conical element;
• f. wall means integral with said tubular body to retain said feeler balls within said guide channels;
• and
• g. coaxial centering sleeve means detachably engaged over said tubular body and said wall means to surround said tubular body over at least a portion of the length thereof, said sleeve means provided with transverse openings to permit passage of said feeler balls, whereby said centering sleeve means may be removed and replaced by another centering sleeve means detachably engaged over said tubular body and said wall means to surround said tubular body over at least a portion of the length thereof and provided with transverse openings to permit passage of said feeler balls.