Here's how to cut steel sheet metal using a few different methods.
Varies
Intermediate
$10 - $60
Introduction
Learn how to cut sheet metal with our step-by-step guide showing multiple techniques for precise, safe cuts for your DIY projects.
When cutting sheet metal, it’s crucial to use the correct methods to get the best results while staying safe. You may need to know how to cut sheet metal while working on DIY craft projects, gutter repair, ductwork, or metal roofing.
Sheet metal is made from different materials and comes in various thicknesses, known as gauges. An easy way to remember sheet metal thickness is that the higher the gauge number, the thinner it is. The thicker the sheet metal, the higher the cost tends to be. Metals such as copper, aluminum, brass, and cold-rolled steel are generally soft, and tin snips are usually suitable for cutting these softer metals.
Most strong and thick sheet metals will require power tools for cutting, such as an angle grinder, band saw, rotary tool, circular saw, or chop saw. I used 22 gauge cold-rolled steel sheet metal for demonstration purposes and different common household tools to cut it.
Tools Required
- Angle grinder
- Carbide metal cutting blades
- Carbide tip scribe
- Carpenter Square
- Circular saw
- Clamps
- Drill w/ bits
- Portable band saw
- Saw horses
- Shop vac
- Tin snips
Materials Required
- 2X4 scrap lumber for straightedge
- Sheet metal
Project step-by-step (5)
How to cut sheet metal with tin snips
- Wear work gloves and eye protection to avoid cutting yourself and protect yourself from flying metal shards.
- Mark the sheet metal where you’d like to cut it with a carbide-tipped scribe, pencil, or marker.
- Use a stable bench or table to support your sheet metal. Hold the sheet over the edge or put 2x4s underneath the metal and clamp it down.
- Use a carbide drill bit to drill a hole in the metal, large enough for the bottom blade of the tin snips to fit into. Since I am cutting a circle, I am using green tin snips.
- NOTE: Tin snips have three different colored handles, each serving a specific purpose. Tin snips with green handles are designed to cut in the right direction, while those with red handles are designed to cut in the left direction. Tin snips with yellow handles are used to cut straight lines.
- Start by inserting the bottom blade of the tin snips into the hole drilled in the center of the sheet metal. Just like cutting with scissors, fully open the blade and squeeze down to cut along the marked line. Follow the circle until you reach the end of the cut.
- Use a metal file to remove any sharp edges left after cutting metal. File in one direction.
- Repeat this process for a straight-cut line, except you will use yellow tin snips.
How to cut sheet metal with an angle grinder
- Before starting, make sure the angle grinder is unplugged. Install the appropriate metal cutting disk for your angle grinder. Use the side support handle if you have one for a better grip.
- Mark the sheet metal where you’d like to cut it with a carbide-tipped scribe, pencil, or marker.
- To prevent the sheet metal from moving while being cut, use clamps to secure it near the edge of the workbench. Although it’s not essential, you can also use a piece of wood to guide cutting in a straight line.
- Put on your safety glasses, mask, hearing protection, and gloves. Remove anything flammable from the work area, as sparks will fly.
- Before you start the angle grinder, double-check that the rotation arrow on the grinder points towards the metal. Start the grinder and gently cut a groove along your marked line. You don’t need to apply much force; just let the grinder’s weight do the cutting. A piece of wood can also be used as a guide for cutting in a straight line, although it is not essential.
- Once the sheet metal has been completely cut, turn off the angle grinder, unclamp the metal, and file the edge smooth.
How to cut sheet metal with a portable band saw
- Draw on the metal where you want to make your cut.
- Clamp down the metal to saw horses or a workbench to prevent it from moving while cutting.
- Put on safety glasses, a mask, hearing protection, and gloves. Clear the work area of anything flammable because sparks may fly.
- Pull the trigger and start your cut at a slight angle to ensure the portable band saw blade is in alignment with your mark. When you begin cutting down your line, adjust the band saw so that the shoe rides smoothly along the bottom side of the sheet metal until the cut is complete.
- Once the blade has stopped, release the clamps from the cut metal and file the edge smooth.
How to cut sheet metal with a circular saw
- Replace your wood cutting blade with a carbide metal cutting blade. Unplug the saw before swapping blades. The thinner the metal, the higher-tooth blade you need. Refer to the blade packaging to verify you have the appropriate blade for your project.
- Secure the sheet metal with clamps to prevent movement during cutting. Keep it near the edge of the workbench for stability, or, depending on the size of your sheet metal, use saw horses.
- Wear safety glasses, a mask, hearing protection, and gloves. Remove anything flammable from the work area, as sparks may fly.
- Mark the sheet metal where you’d like to cut it with a carbide-tipped scribe, pencil, or marker.
- Use a piece of wood clamped down as a straight-edge guide for the saw to stay on course.
- Connect a vacuum hose compatible with your saw to minimize the metal chips from flying. Be sure the vacuum doesn’t contain flammable dust or a vacuum bag. Hot metal shavings can quickly ignite these things.
- Turn on the saw and fully engage the blade before it touches the metal. Cut slowly. Allow the saw to work without applying excessive force. For anything thicker than 22-gauge sheet metal, use stick wax or another lubricant to assist in cutting it. Lubricant ensures blade longevity but makes cutting a bit more messy. As you reach the end of the cut, stabilize the side with the straight edge so it doesn’t bend under the weight.
- Once the cut is complete, you can release the clamps from the sheet metal and file the edge smooth. Check and empty the shop vac for fires.
FAQ
What kind of wheel do I need to cut metal with an angle grinder?
A metal cut-off disc or a diamond blade disc is suitable for cutting metal rebar, steel bars, stainless steel, cast iron, and angle iron.
Can you cut sheet metal with a Dremel?
Yes, you can use a Dremel metal cut-off wheel to cut most metals. Refer to the packaging of the specific Dremel cut-off wheel to see its capabilities.
What is the cheapest saw for cutting thin metal?
The cheapest way to cut thin metal would be with tin snips or a hacksaw.