the threaded hole. Tap extractors are used to remove
broken taps (fig. 1-44, view A).
Screw extractors (view B) are straight, with
spiraling flutes at one end.
These extractors are
available in sizes to remove broken screws having
1/4- to 1/2-inch outside diameters (ODs). Spiral
tapered extractors are sized to remove screws and
bolts from 3/16 inch to 2 1/8 inches OD.
Most sets of extractors include twist drills and a
drill guide. Tap extractors are similar to the screw
extractors and are sized to remove taps ranging from
3/16 inch to 2 1/8 inches OD.
To remove a broken screw or tap with a spiral
extractor, first drill a hole of proper size in the screw
The size hole required for each screw
extractor is stamped on it. The extractor is then
inserted in the hole, and turned counterclockwise to
remove the defective component.
PIPE AND TUBING CUTTERS AND
Pipe cutters (fig. 1-45) are used to cut pipe made
of steel, brass, copper, wrought iron, or lead. Tube
cutters (fig. 1-45) are used to cut tubing made of iron,
steel, brass, copper, or aluminum.
difference between pipe and tubing is that tubing has
considerably thinner walls. Flaring tools (fig. 1-46)
are used to make flares in the ends of tubing.
Two sizes of hand pipe cutters are generally used
in the Navy. The No. 1 pipe cutter has a cutting
capacity of 1/8 inch to 2 inches, and the No. 2 pipe
cutter has a cutting capacity of 2 to 4 inches. The
pipe cutter (fig. 1-45) has a special alloy-steel cutting
wheel and two pressure rollers, which are adjusted and
tightened by turning the handle.
Most TUBE CUTTERS closely resemble pipe
cutters, except that they are of lighter construction. A
hand screw feed tubing cutter of l/8-inch to 1
l/4-inch capacity (fig. 1-45) has two rollers with
cutouts located off center so that cracked flares may
be held in them and cut off without waste of tubing.
It also has a retractable cutter blade, which is adjusted
by turning a knob. The other tube cutter shown is
designed to cut tubing up to and including 1 inch OD.
Rotation of the triangular portion of the tube cutter
within the tubing will eliminate any burrs.
FLARING TOOLS (fig. 1-46) are used to flare
soft copper, brass, or aluminum. The single flaring
Figure 1-45.-Pipe and tubing cutters.