is generally the most common of the hand drills used in
Army aircraft maintenance.
Use. The following paragraphs describe the
techniques for using hand drills.
Placing bit in chuck. To place the drill bit
in the chuck, proceed as follows:
Hold the shell of the chuck while turning
the handle to open the jaws.
When the jaws are apart far enough to
accept the drill bit, insert it until the end
seats in the bottom of the chuck.
Tighten the chuck by turning the handle to
close the jaws. Ensure that the bit is
machined into the jaws, as shown in figure
Breast drill. Proceed as follows:
Turn the crank handle with one hand while
holding the side handle with the other
Apply feed pressure by leaning against
the breast plate.
Drilling. When drilling with the hand drill,
operate the crank with one hand, and with the other
hand guide the drill by holding the handle on the end of
Care. Observe the following practices for the
care and upkeep of hand drills:
Apply a light coat of oil to all metal
With a rag, clean gear teeth of dirt, wood,
and metal shavings.
Hang drills on a rack in a dry location.
4-13. Drill Bits. A drill bit is a pointed tool that is
rotated to cut holes in material. It is made of carbon
steel or harder alloy steels, depending upon the type of
Description. A typical drill bit and its parts are
shown in figure 4-83. Some of these parts are
explained in the following paragraphs.
Figure 4-80. Breast Drill
Figure 4-81. Hand Drill