Reaming or boring is called a chip removal process or a machining operation that is carried out to achieve a good surface finish with certain dimensional tolerances, or simply to enlarge holes that have been previously drilled with a drill bit to a slightly smaller diameter.

The reaming is carried out with a tool called a reamer (calisuar in some countries), to which two movements are communicated, one of rotation around its axis, and another of rectilinear movement along said axis.

Before reaming a hole, it must have been drilled, leaving a certain thickness, which depends on the diameter of the hole and the material of the piece. This process can be carried out by hand or automatically with a machine tool that allows these movements, such as a lathe, a milling machine or a drilling machine. In automatic reaming, the part is clamped to the machine by means of a vise, chuck "Chuck (engineering)") or something similar.

For an optimal result, in the reaming process it is essential to prepare the drilling leaving the material just inside the hole, since if there is insufficient material, the tool will rub against the material before achieving the objective, wearing out and losing diameter; but, on the contrary, it is not appropriate for there to be an abundance of material inside the perforation.

This process is carried out at much lower speeds compared to the drilling process, eliminating a very small amount of material.

To carry out a good reaming process, you must select the optimal type of reamer appropriate for the speeds and feeds at which you are going to work, without forgetting that you must first ensure that the drilled holes are of the appropriate diameter.

The material or piece to be reamed must be well supported and the machine spindle must have as little play as possible, or rather zero play, just like that between the reamer handle and the sleeve or bushing; Otherwise, you will encounter misalignment, and this will cause the reamer to cut more chips than it should.

It must not be forgotten that for a good reaming process, and better maintenance of the tool, the recommended lubricants must be used, and thus premature deterioration of the tool will be avoided.