ARROWLESS DIMENSIONING

Drawing $21$ A$044$ lends itself to a simplified drafting technique

called arrowless dimensioning. Instead of using dimension lines,

the dimension figures are placed at the ends of the extension or cen$-$

ter lines. This method is limited to datum dimensioning, however.

The datum surfaces on the drawing are identified by $0$ : thus each

dimension figure represents its actual distance from zero.

INSTRUCTIONS: Refer to drawing $21$ A$044$ to answer the following

questions.

What simplified method of dimensioning was used for locating

the holes?

Why do the two overall dimensions appear inside of parentheses?

What is the MMC of the $\mathrm{.}312$ diameter holes?

How far apart are the counterbored hole and the countersunk hole

$($C to $C)?$

What is the maximum tolerance between any two hole locations?

What thread form is specified for the tapped holes?

What class of fit is specified for the tapped holes?

What is the thread depth of the blind hole?

Is the tap drill smaller for the fine thread or the coarse thread?

What TPI is specified for the fine thread?

What is the pitch $($decimally$)$ of the coarse thread?

What is the pitch $($decimally$)$ of the extra$-$fine thread?

What is the diameter of the tapped hole chamfers?

What is the maximum depth of the counterbore?

What is the approximate depth of the spotface?

Would print tolerance permit the use of a $\frac{7}{32}$ tap drill for the fine

thread?

Would print tolerance permit the use of a $\frac{3}{16}$ tap drill for the

coarse thread?

How many full threads will the coarse tapped hole contain? $($Dis$-$

regard chamfer.$)$

How many full threads, at minimum depth, will the fine tapped

hole contain? $($Disregard chamfer.$)$

$\mathrm{.}510$

$\mathrm{.}03-\mathrm{.}06$

$16$

$17$