If No Tap Drill Chart Is Available, the Correct Drill $\frac { 1 } { 3 }$

Multiple Choice

If no tap drill chart is available, the correct drill size (TDS) can be found by using the formula TDS = OD - P, where OD is the outside diameter and P is the pitch of the thread (the distance between the successive threads) . Find the tap drill size for a $\frac { 1 } { 3 }$ in. outside diameter if the pitch is $\frac { 1 } { 18 }$ in.

A) $\frac { 5 } { 36 }$ in.
B) $\frac { 4 } { 9 }$ in.
C) $\frac { 5 } { 18 }$ in.
D) $\frac { 2 } { 9 }$ in.
E) $\frac { 1 } { 6 }$ in.