This affects only the mechanical properties

This affects only the mechanical properties of the material, leaving a good surface finish.
A reamer is a metalworking tool used to create an accurate sized hole. Reamers must combine both hardness in the cutting edges, for long life, and toughness, so that the tool does not fail under the normal forces of use.
Taper pin reamers, is used to make a tapered hole to later receive a tapered pin. For producing machine tools, the shank type is usually a straight round shank to be held by a collet or with a flat for a set screw, to be held by a solid screwholder. A typical reamer consists of a set of parallel straight or helical cutting edges along the length of a cylindrical body. The chamber reamer is inserted into the bore of a barrel and held stationary while the barrel is turned around it. A taper pin is a self tightening device Lathe Tool due to the slow angle of the taper. Rose reamers, has no relief on the periphery and is offset by a back taper to prevent binding. The process is called reaming.
For superior finish of the hole and long life of the reamer, the reamers should be used to remove small quantity of materials. The reamer slowly cuts away material, leaving a chamber capable of accepting a specific cartridge. This is to compensate for the difficulty of starting a hole by hand power alone. Hand reamer, has a longer taper or lead in at the front than a machine reamer. It also allows the reamer to start straight and reduce the risk of breakage. Shell reamers, are designed for reaming bearing and other similar items. They may be driven into the tapered hole such that removal can only be done with a hammer and punch.
Chamber reamer, is a specific type of fluted reamer used by gunsmiths manufacturers to cut the chambers of a handgun, riffle and shotguns. Because the reamer and work piece are pre-aligned by the machine there is no risk of it wandering off course. They may be used as a hand tool or in a machine tool, such as a milling machine or drill press.

For more information about Read tool masterand also read about rolling dies & milling cutters. Reamers are multi-fluted, end-cutting tools used to finish previously formed holes to exact diameters.
The various types of reamers are discussed here. The flutes may be straight or spiral. Reaming removes a very thin layer of stressed and disturbed material caused by drilling a hole. They are primarily used as roughing reamers. Reamers should not be used to enlarge holes. In addition the constant cutting force that can be applied by the machine ensures that it starts cutting immediately. Machine reamer, only has a very slight lead in. For hand tools, the shank end is usually a square drive, intended for use with the same type of wrench used to turn a tap. They are fluted almost their whole length