TM 9-243
TYPES AND USES
Reamers are used to enlarge and true a hole. They are
also used to remove burrs from the inside diameters of
pipes and drilled holes. The reamer consists of three
parts, the body (1), the shank (2), and the blades (3).
The shank has a square tang to allow the reamer to be
held with a wrench for turning.
SOLID STRAIGHT-HOLE REAMER
A solid straight-hole reamer is made of one solid piece
of high-speed steel having a straight shank and straight
(1) or spiral flutes (2). The cutting edges, or lands,
between the flutes are usually evenly spaced. Some
have irregularly spaced lands to prevent the tool from
chattering. They come in sizes from 1/16 inch to
include 3-inch diameters. Reamers are also available in
sets containing 25 reamers in 1/64-inch increments from
1/8 inch to 1/2 inch. The sets may be mixed to include
straight and taper pin reamers. Each reamer size is
stamped on the shank of the tool. Solid straight-hole
reamers are used for most work since they are the most
accurate and the most rugged of the straight-hole
reamers.
SOLID TAPER-PIN REAMER
Solid taper-pin reamers are used to finish tapered holes
for the insertion of tapered pins or other tapered parts.
They are made with a standard taper of 1/4 inch per
foot. Solid taper-pin reamers come with straight (1) or
spiral flutes (2). Sizes range from 5/0 to 14, with the
diameter at the large end ranging from 0.0984 to 1.5412
inches. They also come in sets of 10, sizes 3/0 to 7, and
a set of 11, sizes 0 to 10. They are also included in
mixed sets of straight and taper-pin reamers.
EXPANSION REAMER
Expansion reamers are adjustable, and their sizes may
be changed by 1/8 inch for a 1-inch reamer and 5/16
inch for a 2-inch reamer. The expansion reamer is
made of carbon steel and has longitudinal cuts in some
of its flutes. It is hollowed out and threaded to receive a
tapered screw plug. The diameter of the reamer is
changed by screwing in or backing out the screw plug.
The standard sizes range from 1/4 inch to 1 inch, by
32nds. A 1/4-inch expansion reamer will enlarge the
hole to a 9/32-inch hole, etc. It is used for general
purposes and is considered the most practical reamer.
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