202 Print Reading for Industry
Local notes, also referred to as specific notes or
callouts, apply only to certain features or areas. They
are positioned near the feature or area to which the
note apply. A leader is used to indicate the feature
or area. See Figure 11-2.
Sometimes local notes use numbers enclosed
in an equilateral triangle. This is called a flag. See
Figure 11-3. The actual note text appears in a central
location with other “flagged” local note text. This
technique can help keep the area near the views
more free from clutter.
Holes
Often, a hole has specifications associated
with it. For example, a hole may be counterbored
or countersunk. Additionally, especially on older
drawings, the type of operation may be specified.
These specifications are usually identified in a note.
Drilled and Reamed Holes
Drilled holes are created with a twist drill, not a mill
cutter. As mentioned, ASME standards discourage
specifying whether or not the hole must be
manufactured by drilling. If specified, drilled holes
are usually specified by the diameter of the drill bit.
The number of holes and depth may also be
specified. Figure 11-4 shows how symbols are
used in local callouts for holes. Standard practice
recommends specifying the holes as 2X ˚.250 with
the leader line only pointing to one hole. The depth
symbol is used in front of the depth value. If the
depth is specified as
THRU
(for through), the hole
passes entirely through the feature. Also illustrated
in Figure 11-4 are local notes for counterbore and
countersink, which are enlargements to the hole
opening.
Review Figure 9-3 in the dimensioning unit for
a thorough review of symbols used in local notes
for holes. The symbols in current standards explain
96 DP DIAMOND
KNURL – 30° RAISED
DRILL SPOT FOR
SET SCREW
UNDERCUT
.125 WIDE x .062 DEEP
#808 WOODRUFF
KEYSEAT
.531
Figure 11-2.
Local notes should use symbols that have been standardized for several years. In former practice, words were in
common use, as shown here.
1
2
3
4
.030 X Chamfer.
This surface to be coplanar with
surface marked "Y".
Rubber stamp part number here.
Mount in chuck using this surface.
Figure 11-3.
A flagged local note is a number enclosed in an equilateral
triangle. The actual note text appears in a central location
with other local note text, as shown here.