Letter drills decrease in size from A to Z.

Letter drills decrease in size from A to Z.

• A. True
• B. False
• C. Not sure
• D. Not applicable

Answer: (B)

Letter drill sizes are arranged so that each subsequent letter represents a larger diameter. In this system, A is the smallest standard drill size and Z is one of the largest, with every step toward Z increasing the hole size. So the statement that letter drills decrease in size from A to Z is not correct. This ascending progression helps machinists quickly choose a drill close to the desired hole diameter—earlier letters for smaller holes, later letters for larger ones.

Letter drill sizes are arranged so that each subsequent letter represents a larger diameter. In this system, A is the smallest standard drill size and Z is one of the largest, with every step toward Z increasing the hole size. So the statement that letter drills decrease in size from A to Z is not correct. This ascending progression helps machinists quickly choose a drill close to the desired hole diameter—earlier letters for smaller holes, later letters for larger ones.