A tap marked 5/16 X 24 UNF will create threads with what threads per inch?

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Multiple Choice

A tap marked 5/16 X 24 UNF will create threads with what threads per inch?

The main idea is that the number after the diameter is the number of threads per inch. In a tap marked 5/16 X 24 UNF, the UNF denotes Unified National Fine, a finer thread series than UNC. For a 5/16 inch diameter in this fine series, the standard pitch is 24 threads per inch. So the tapped hole will have 24 TPI. The other numbers would correspond to different diameters or thread series (for example, a coarse UNC 5/16 would use 18 TPI), but this marking specifies 24 TPI.

The main idea is that the number after the diameter is the number of threads per inch. In a tap marked 5/16 X 24 UNF, the UNF denotes Unified National Fine, a finer thread series than UNC. For a 5/16 inch diameter in this fine series, the standard pitch is 24 threads per inch. So the tapped hole will have 24 TPI. The other numbers would correspond to different diameters or thread series (for example, a coarse UNC 5/16 would use 18 TPI), but this marking specifies 24 TPI.

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