What is the typical tolerance range for drilling?

• A. +-0.002-0.010 in
• B. +-0.001-0.005 in
• C. +-0.005-0.015 in
• D. +-0.010-0.020 in

Answer: (A)

Drilling tolerance is about how close the drilled hole size tends to be to the target during a standard drilling operation. In typical shop conditions, holes produced by common drilling processes usually fall within a few thousandths of an inch, roughly from 0.002" up to 0.010" deviation. This reflects the balance between tool deflection, setup stability, and material behavior that you see with ordinary drills. Tighter tolerances, around 0.001" to 0.005", can be achieved but require more control or finishing steps like reaming; looser tolerances, such as 0.010" to 0.020", are not typically expected from standard drilling alone. So, the range of about ±0.002" to ±0.010" best represents the common drilling outcome. If you need smaller holes and tighter control, you’d add finishing operations after drilling.