USE/CARE OF HANDTOOLS & MEASURING TOOLS - OD1621 - LESSON 2/TASK 2
(a) Center Punch. A center punch has a narrow cone-shaped point
terminating in a sharp 90 conical tip. The stock on a center punch may be
octagonal, round, or square in shape, with or without knurling.
Center
punches range in size from 1/8 inch diameter stock to 5/8 inch with a length
of 3 to 6 inches.
An automatic center punch is also available.
Where other center punches
require a hammer blow to mark metal, the automatic center punch contains a
mechanism which automatically strikes a blow of the required force when the
punch is in the desired position and is pushed forward by hand pressure. It
has an adjustable cap for regulating the stroke and the point is removable
for regrinding and replacement.
Center punches are normally used for
starting holes to be drilled.
(b) Drift
and Alining Punches.
Drift and alining punches are
normally tapered to
a 1/8, 3/16, 7/32, 1/4, 5/16, 3/8, or 1/2 inch point,
and range in length
from 7 to 15 inches. Drift and alining punches are used
to line up holes in
metal work.
(c) Drive Pin Punch. Drive pin punches are used for driving out
straight or tapered pins. The standard drive pin punch tapers to a point
ranging in diameter from 0.03 to 1/2 inch. Standard drive pin punches are
issued in sets of 9, as well as individually. Some drive pin punches are
straight (without taper). The shanks may be knurled for better gripping, or
hexagon shaped.
Common lengths range from 3 to 6 inches, however, some
drive pin punches have long tapers and an overall length of 9 inches.
(d) Prick Punch. The prick punch is used for marking soft metal,
such as brass, and has a long tapered cone-shaped point terminating in a
sharp 30 conical tip.
(e) Blacksmith's Punch.
A blacksmith's punch is equipped with a
handle to protect the user from contact with hot metal, and to provide a
better grip when punching holes in hot metal.
Blacksmith's punches are
issued with a tip having a diameter of 1/4 inch to 1 inch.
(f) Track Pin Punch.
A track pin punch is especially designed to
drive out pins from railroad
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