If a hole diameter is specified as 0.17187 inches, which drill bit size will result in the closest fit?

To determine which drill bit size will provide the closest fit to a hole diameter of 0.17187 inches, it is important to convert the fractional sizes of the drill bits to their decimal equivalents. This allows for a direct comparison with the specified hole diameter.

Calculating the drill bit sizes in decimals:

• The size of 9/64 inches is approximately 0.140625 inches.

• The size of 10/64 inches (which simplifies to 5/32) is approximately 0.15625 inches.

• The size of 11/64 inches is approximately 0.171875 inches.

• The size of 12/64 inches (which simplifies to 3/16) is approximately 0.1875 inches.

Comparing these decimal values to the specified hole diameter of 0.17187 inches, the drill bit size of 11/64 inches, which measures 0.171875 inches, is exceedingly close to the specified measurement. The small difference indicates it will result in the closest fit.

This relationship emphasizes the importance of precise measurements in aviation maintenance, where small variances can significantly impact the assembly and functionality of aircraft components. When specifying hole sizes or fitting components, it is crucial to select