Limit gauges are used to:

Explanation:-

Plain gauges -

• Plain gauges are used for checking plain (unthreaded) holes and shafts.
• Gauges are inspection tools without a scale that serve to check the dimensions of the manufactured parts.
• Instead of measuring actual dimensions, the conformance of the product with tolerance specifications can be checked by "GO" and "NOT GO" gauges.
• These gauges represent the limit sizes of the workpiece, as per the specified product tolerances.
• A "GO" gauge represents the maximum material condition of the product and conversely, a "NOT GO" gauge represents the minimum material condition.

Classification of plain gauges - They are classified:

• According to their type

1. Standard gauges
2. Limit gauges

• According to their purpose  

1. Workshop gauges
2. Inspection gauges
3. Reference or master gauges

• According to the form of the tested surface

1. Plug gauges for checking holes
2. Snap and ring gauges for checking shafts

• According to their design

1. Single-limit and double-limit gauges
2. Single-ended and double-ended gauges
3. Fixed and adjustable gauges.

• Both ring and plug gauges are available in two designs, ‘GO’ and ‘NO-GO’.