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(design engineering)
A tool used to enlarge, shape, smooth, or otherwise finish a hole.



a multiblade metalcutting tool for the precision and fine machining (reaming) of holes after their preliminary machining using a drill, countersink reamer, or boring cutter. Chucking reamers are used on lathes, and hand reamers are used in fitter’s work.

Cylindrical, tapered, and step reamers are distinguished by the shape of the reamed hole; straight-flute and spiral-flute reamers are distinguished by the shape of the cutting edges; and reamers (with a shank) and shell reamers (with a hole) are distinguished by the mounting means used. In addition, solid and compound reamers, reamers with soldered-on cutting edges, reamers with cutting edges that are cemented or mechanically attached, and adjustable and floating reamers are distinguished on the basis of their design.

Figure 1. Diagram of a reamer: (1) cutting section, (2) finishing section, (3) shank, (4) neck, (5) body, (6) cutting edge

The body of a reamer (see Figure 1) consists of cutting and finishing edges. The cutting edges are sharply honed, and a heel 0.1–0.3 mm wide is left on the finishing teeth. The end of the finishing section is made with a reverse taper in the direction of the shank in order to reduce the friction of the reamer against the wall of the hole.


Semenchenko, I. I., V. M. Matiushin, and G. N. Sakharov. Proektirovanie melallorezhushchikh instrumentov. Moscow, 1963.
Kosmachev, I. G. Karmannyi spravochnik tekhnologa-instrumental’shchika, 2nd ed. Leningrad, 1970.
Rezanie konstruktsionnykh materialov, rezhushchie instrumenty i stanki. Moscow, 1974.



A tapered bit having sharp, spiral, fluted cutting edges along the shaft; used to enlarge an opening, to cut the burrs from the inside of pipe, etc.
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