Combined SI Metric and Whitworth
Number of Blades 49
Thread per mm
METRIC 0.4, 0.5, 0.7, 0.75, 0.8, 0.9, 1.0 1.25, 1.50, 1.75, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0
IMPERIAL 4, 4.5, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 18, 19, 20, 22, 24, 25, 26, 28, 30, 32, 36, 40, 48, 60

Accurately milled steel blades
Designed to check both internal and external thread forms
Marked with nominal size on each blade
All blades fixed in a steel sleeve
Screw cutting gauge included - 60 Degrees