Adobe ILLUSTRATOR 6.0, Online Manual, Page: 804 / 893

804
Stroked shapes that appear to be
aligned do not line up when you
preview or print.
Sharp spikes appear in stroked letters,
such as
M
and
W
, in printed output.
The miter line join style is causing the
corner points to extend beyond the
actual anchor points. When you specify
this style of line join, the outer edges of
two lines that form a corner extend until
they meet. If the lines form a sharp
angle or have a heavy line weight, the
corner can extend farther than
expected.
To line up corners properly, select the
path with the jutting corners. Choose
Object
>
Paint Styles, and change the
line join style to either the bevel (flat) or
the round join option.
You can also set a lower miter limit for
mitered corners. Illustrator then will use
a shorter path (and smaller angle) when
determining at what point to switch
from a bevel join to a miter join. See also
To select a Joins option for a line: .