Thread Gauge
Peter Hirt Thread Gauge Feelers are available from the smallest size 0-200 (ball diameter 0.200 mm) up to size 12 (ball diameter 4.000 mm). The current smallest size Thread Gauge Feeler 0-200 with a ruby ball diameter of 0.200 mm, is sized for the measurement of threads to size M1.7. The Thread Gauge Feelers are available individually or in a protectiv wooden box as a 12pc, 13pc or 14pc set.