Rebar is a metal bar which is mainly used for reinforcing concrete slabs. The rebar is placed in the area in which concrete is poured in layers or grids. The rebar may then be welded together or bound using steel wire. When it becomes necessary to cut rebar, the best possible cutting tool is a rotary cut off wheel. In the absence of this tool, however, rebar can be cut with a hack saw.
Measure the length to which the rebar must be cut using a measuring tape.
Position the rebar on a solid, steady work surface. Make sure that the point that you will cut is a few inches from the work surface, but not so far that the end of the rebar will vibrate while you are cutting.
Clamp the rebar securely to the work surface, with the clamp positioned as near to the point where the rebar will be cut as the work surface allows.
Position the hack saw on the point where you will make your cut. Make short cutting movements with the hacksaw until you have created a groove in the metal for the blade to follow, then make long steady cuts using as much of the saw blade as possible.