Arm paper cutters are great for cutting down multiple pieces of typing paper, especially when they are new and sharp, but arm paper cutters should not be used to make straight cuts on a mat board. After some use, the arm blade tends to become duller in some areas than in others, easily creating ragged edges. Because you want your viewer to notice your artwork and not your mat board, you shouldn't provide any excuse for his eyes to be distracted by details like tearing.
Straight cuts on a mat board should be created using repeated light cuts with a straight knife, rather than one pass made with heavy pressure. A common utility knife can accomplish this, as long as the razor blade inside is sharp and doesn't have a broken tip. Dedicated mat-cutting knives are also available that are smaller and whose blades are easier to exchange. These are made by such brands as X-ACTO, Logan and Dexter.
The distinctive look of matted artwork is created by the bevel-cut window. This cut is made at a 45-degree angle to the face of the mat board. Mat-cutting systems provide a system by which a bevel cutter travels along a bar, creating a straight line while making an angled cut, as long as you provide steady pressure. Bevel cutters consist of a simple hand-held device into which a common razor blade is placed. A knob adjusts the depth of the bevel cut. Unlike straight cuts, bevel cuts must be made in one strong stroke; realigning the blade in just the right place to make multiple cuts without shredding the mat board is very difficult.
Straight knives are used to cut a piece of mat board that is larger than your artwork. This can be whatever size you want or need, although some standard sizes include 8 inches by 10 inches, 11 by 14, 16 by 20, and 20 by 24. The artwork is measured to determine the size of your window, and some math is involved to determine where to place the window. The window should be centered left to right, with a slightly larger space below the window than above it. These lines should always be made in pencil on the backside of the mat board. The mat board is then placed in the mat-cutting system along the guides that help you determine where to insert the bevel-cutter. The cutter is then either pushed towards you or away from you, depending on the design. Repeating this cut three more times results in a finished mat board window.