the body of the machine fits comfortably in the
palm of the hand, and the rotating eraser can be
directed as accurately as a pencil point. Refills for
either ink or pencil erasing are available.
CAUTION: Do not hold the electric eraser
steady in one spot, or you may easily wear a hole
or damage the surface of the material being
erased.
When there are many lines close together and
only one needs to be removed or changed, the
desired lines may be protected by an erasing
shield, as shown in figure 2-5.
Finely pulverized gum eraser particles are
available in squeeze bottles or in DRY CLEAN
PADS for keeping a drawing clean while you
work on it. If a drawing or tracing is sprinkled
occasionally with gum eraser particles, triangles,
T squares, scales, french curves, and the like, not
only tend to stay clean themselves, but also tend
to clean the drawing or tracing as they are
moved over the surface.
Before a drawing is inked, it is usually
prepared by sprinkling on POUNCE (a very
fine bone dust) and then rubbing in the pounce
with a felt pad on the container. Pounce helps
to prevent a freshly inked line from spreading.
A draftsman’s DUST BRUSH should be used
for brushing dust and erasure particles off a
drawing.
29.273
Figure 2-5.-Use of an erasing shield.
DRAFTING TABLES WITH BOARDS
Most EA shops are furnished with standard
drafting tables with drafting boards, as shown in
figure 2-6. The majority of this furniture is
easily adjustable to the users’ needs. The height
of the table should be such that if you desire to
work in a standing position, you can do so without
stooping or holding your arms in a raised
position. Hinged attachments for the drafting
board are provided to adjust the incline so
that your line of sight will be approximately
perpendicular to the drafting surface. Your
drafting stool should be high enough in relation
to the table for you to see the whole drafting
board but not so high that you are uncomfortably
seated.
The drafting boards contained in the drafts-
man kit are constructed of joined strips of
softwood, usually clear white pine or basswood.
They are equipped with hinged attachments for
securing the board to a table or fabricated base.
If suitable bases are not available, table bases may
be constructed at the unit carpenter shop.
You should consider only the left-hand
vertical edge as a working edge for the T square
if you are right-handed (the right-hand edge if you
are left-handed). The T square should never be
used with the head set against the upper or lower
edge of the board, as the drafting board may not
be perfectly square.
The drafting board should be covered. A
variety of good drafting board cover material is
available. Available cover materials are cellulose
acetate-coated paper, vinyl, and mylar film. The
vinyl drafting board covers have the added
advantage of being able to close up small holes
or cuts, such as those made by drafting compasses
or dividers. In general, these covers protect the
drafting board surface by preventing the drafting
pencil from following the wood grain, by
reducing lighting glare, and by providing an
excellent drafting surface.
Since you will be constantly using your eyes,
it is important that your working area be well
lighted. Natural light is best, if available and
ample, although in the majority of cases
acceptable natural light will be the exception
rather than the rule. Drafting rooms are usually
lighted with overhead fluorescent fixtures.
Ordinarily, these fixtures are inadequate in quality
and intensity of light. Adjustable lamps will
improve the lighting conditions. The most popular
type of adjustable lamp is the floating-arm
fluorescent fixture that clamps onto the drafting
2-6
