s termed, an example that it is
desirable for the student to draw in various sizes, as it is
representative of a large class of work.

These eyes often have an offset, and an example of this is given in
Figure 195, in which A is the centre line for the stem distant from the
centre line B of the eyes to the amount of offset required.

[Illustration: Fig. 194.]

[Illustration: Fig. 195.]

[Illustration: Fig. 196.]

[Illustration: Fig. 197.]

In Figure 196 is an example of a connecting rod end. From a point, as A,
we draw arcs, as B C for the width, and E D for the length of the block,
and through A we draw the centre line. It is obvious, however, that we
may draw the centre line first, and apply the measuring rule direct to
the paper, and mark lines in place of the arcs B, C, D, E, and F, G,
which are for the stem. As the block joins the stem in a straight line,
the latter is evidently rectangular, as will be seen by referring to
Figure 197, which represents a rod end with a round stem, the fact that
the stem is round being clearly shown by the curves A B. The radius of
these curves is obtained as follows: It is obvious that they will join
the rod stem at the same point as the shoulder curves do, as denoted by
the dotted vertical line. So likewise they join the curves E F at the
same point in the rod length as the shoulder curves, both curves in fact
being formed by the same round corner or shoulder. The centre of the
radius of A or B must therefore be the same distance from the centre of
the rod as is the centre from which the shoulder curve is struck, and at
the same time at such a distance from the corner (as E or F) that the
curve will meet the centre line of the rod at the same point in its
length as the shoulder curves do.

[Illustration: Fig. 198.]

Figure 198 gives an example, in which the similar curved lines show that
a part is square. The figure represents a bolt with a square under the
head. As but one view is given, that fact alone tells us that it must be
round or square. Now we might mark a cross on the square part, to denote
that it is square; but this is unnecessary, because the curves F G show
such to be the case. These curves are marked as follows: With the
compasses set to the radius E, one point is rested at A, and arc B is
drawn; then one point of the compass is rested at C, and arc D is drawn;
giving the centre for the curve F by a similar process on the other
side of the figure, curve G i