Correct option is A
For metric threads, the tap drill size is calculated using the formula:
Drill Size = Major Diameter -Pitch
Where:
· Major Diameter (M10) = 10 mm
· Pitch ( for M10 × 1mm thread ) = 1 mm
Drill Size = 10 - 0.9 = 9.1 mm Thus, the correct drilled hole size for M10 × 1 mm is 9.1 mm .
