Correct option is D
A
tapping hole (also called a
drilled hole for tapping) should be
smaller than the tap size to allow proper thread formation when cutting internal threads using a tap.
Reasons:
·
Allows Proper Thread Engagement:
· A smaller hole ensures that the
tap removes material to form precise threads.
·
Prevents Loose Threads:
· If the hole is too large, the
threads will be shallow and may not hold the bolt securely.
·
Ensures Thread Strength:
· A properly sized tapping hole results in
strong, durable threads.
Example:
· If you need to tap
M10 threads, the recommended tapping hole size is
8.5 mm (smaller than 10 mm).
