How to Cut Steel

The reasons you might need to cut steel are as varied as uses for steel itself. There are many different kinds of steel such as low carbon, medium carbon and high carbon mild steel, and Ferritic, Austenitic, and Martensitic stainless steels. Steel may come in different forms and thicknesses, such as pipe, sheet, bar stock, wire, rebar, etc. This article will focus on how to cut sheet steel.

1. Decide whether you need stainless steel or mild steel for your project. Mild steel is prone to rusting, while stainless steel is corrosion resistant.
2. Determine if you need a hardenable steel for your project.
   • For mild steel, high carbon steel (approximately 1.2% carbon) is necessary if you intend to harden the steel for your project. For stainless steel, you'll need Martensitic, or 400 series.
3. Figure out what thickness of steel you require. Thickness is referred to as "gauge." There is American Wire Gauge (AWG) and Imperial Standard Wire Gauge (SWG - British). In either case, the smaller the number of gauge, the thicker the steel. Wire and sheet steel gauges are comparable.
4. Draw what you want to cut onto the steel with an indelible marker.
   • If you aren't exactly sure what shape or size you want to cut out, you should draw your pattern on poster board before cutting your steel. Cut the poster board and shape it, as best you can, using tape to hold it together. If it has the right shape, or is close, then you are ready to transfer your pattern to the steel. If it isn't quite right, make changes to the poster board pattern before transferring it to the steel and cutting.
5. Cut the steel using your steel cutting tool of choice.
   • There are a variety of sheet steel tools which can be used for making cuts. If the steel is a thin gauge, such as 18 gauge AWG or less, you can probably make do with tin snips. Cutting sheet steel of any gauge is more easily done with a bench shear. Bench shears come in two general types: straight shears, and throatless shears. Straight shears make cuts in straight lines and outside curves. A throatless shear can cut inside curves and other complicated shapes, in addition to outside curves and straight lines. You can also use a nibbler or a jigsaw to cut your steel, but be prepared to go to a lot of effort to clean up the edges of the cuts.

• You'll need to de-burr the edges of the steel to make them safer to handle. This can be done with a file, belt sander or other abrasive. Wear eye protection and hearing protection whenever appropriate.
• Keep in mind that the edges of the steel, no matter what you used to cut it, will be sharp and need to be handled with care. Wearing gloves is a good idea when cutting and handling sheet steel.

• Sheet steel
• Indelible marker
• Poster board (optional)
• Steel cutting tool (tin snips, shear, nibbler, jigsaw, etc.)