The "Go" and "No Go" sizes for a snap gauge like 25H7 indicate the acceptable dimensional limits for a specific feature on a workpiece. In the case of the 25H7 snap gauge, the numbers "25" and "H7" refer to a specific tolerance class and size.
In the ISO system for fits and tolerances, the number before the letter represents the basic size of the hole or shaft, and the letter indicates the tolerance class. In this case:
- "25" is the basic size.
- "H7" is the tolerance class for the hole.