Study the example hole note for specifying $(2)$ holes to be drilled and tapped for $\frac{1}{2^{\text{'}\text{'}}}$ threads thru an aluminum workpiece. List the correct hole note for

specifying $(3)\frac{1}{2^{\text{'}\text{'}}}$ fastener threads ${1\mathrm{.}0}^{\text{'}\text{'}}$ deep in a steel workpiece.

Hint #$1$: the type of thread $($coarse or fine$)$ is dictated by the type of material being threaded $($weaker or stronger$).$ Hint #$2$: blind holes must be tap drilled approximately one

major fastener diameter deeper than the required thread depth.

Example:

hole note specifications:

$\frac{O}{?}$ tap drill diameter $+$ depth;

thread specification $+$ depth;

quantity of holes desired

This specific question:

hole note specifications:

$\frac{O}{?}$ tap drill diameter $+$ depth;

thread specification $+$ depth;

quantity of holes desired

$\frac{1}{2^{?}}$ threads in aluminum:

$27/64"$ THRU;

$1/2-13$ UNC THRU;

$2$ PLACES

$"$ threads in

$\frac{O}{?}$

$n$

$"$;

$,"$DP;

PLACESStudy the example hole note for specifying $(2)$ holes to be drilled and tapped for $1/2$ threads thru an aluminum workpiece. List the correct hole note for specifying $(3)1/2$ fastener threads $1\mathrm{.}0$ deep in a steel workpiece.

Hint #$1$: the type of thread $($coarse or fine$)$ is dictated by the type of material being threaded $($weaker or stronger$).$ Hint #$2$: blind holes must be tap drilled approximately one major fastener diameter deeper than the required thread depth.