to be departed from, in which event an end
view may be added, or the view showing two sides may be given.

[Illustration: Fig 161.]

[Illustration: Fig. 162.]

[Illustration: Fig. 163.]

[Illustration: Fig. 164.]

To draw a square-headed bolt, the pencil lines are marked in the order
shown by figures in Figure 164. The inking in is done in the order of
the letters _a_, _b_, _c_, etc. It will be observed that pencil lines 2,
9, and 10 are not drawn to cross, but only to meet the lines at their
ends, a point that, as before stated, should always be carefully
attended to.

[Illustration: Fig. 165]

To draw the end view of a hexagon head, first draw a circle of the
diameter across the flats, and then rest the triangle of 60 degrees on
the blade _s_ of the square, as at T 1, in Figure 165, and mark the
lines _a_ and _b_. Reverse the triangle, as at T 2, and draw lines _c_
and _d_. Then place the triangle as in Figure 166, and draw the lines
_e_ and _f_.

[Illustration: Fig. 166.]

If the other view of the head is to be drawn, then first draw the lines
_a_ and _b_ in Figure 167 with the square, then with the 60 degree
triangle, placed on the square S, as at T 1, draw the lines _c_, _d_,
and turning the square over, as at T 2, mark lines _e_ and _f_.

[Illustration: Fig. 167.]

If the diameter across corners of a square head is given, and it be
required to draw the head, the process is as follows: For a view showing
one corner in front, as in Figure 168, a circle of the given diameter
across corners is pencilled, and the horizontal centre-line _a_ is
marked, and the triangle of 45 degrees is rested against the square
blade S, as in position T 1, and lines _b_ and _c_ marked, _b_ being
marked first; and the triangle is then slid along the square blade to
position T 1, when line _c_ is marked, these two lines just meeting the
horizontal line _a_, where it meets the circle. The triangle is then
moved to the left, and line _d_, joining the ends of _b_ and _c_, is
marked, and by moving it still farther to the left to position T 2, line
_e_ is marked. Lines _b_, _c_, _d_, and _e_ are, of course, the only
ones inked in.

[Illustration: Fig. 168.]

[Illustration: Fig. 169.]

If the flats are to lie in the other direction, the pencilling will be
done as in Figure 169. The circle is marked as before, and with the
triangle placed as shown at T 1, line _a_, passing through the centre of
the circle, is drawn. By moving