USE/CARE OF HANDTOOLS & MEASURING TOOLS - OD1621 - LESSON 3/TASK 1
CONVERSION CHART - INCHES TO MILLIMETERS.
1 Class I.
between screw and tapped hole.
2 Class II.
Medium or free fit, permitting slight
interference in the worst combination of maximum screw and maximum nut.
3 Class III.
Close tolerances on mating parts may require
this fit, applied to the highest grade of interchangeable work.
4 Class IV.
A fine snug fit, where a screwdriver or wrench
may be necessary for assembly.
An additional Class V, or jaw fit, is recognized for