If you’ve ever tried cutting sheet metal before, you may have experienced some bending or gouging while cutting. You can avoid this by following our guide on how to cut sheet metal for your next DIY projects. All you need is to do is to use the right tools and the proper techniques.
The techniques we’ve listed are versatile and could be used for various purposes whether you are repairing HVAC ducts or doing your personal metal craft projects, which almost always involve working with sheet metal.
So, here are the best ways to cut sheet metal.
Cutting with Tin Snips
One of the most common ways to cut sheet metal is by using tin snips. We could even say it’s the best way to cut sheet metal, although there are other alternatives too. Tin snips are also called aviation snips. They look a lot like scissors and are suitable for cutting soft sheet metals.
You can use either a left cut, a straight cut or a right cut snip depending on the shape of the cut that you want. You can determine the type of cut by looking at the snip’s handle color. Left-cut snips are red, right-cut are green, and straight snips are yellow.
How to Cut Sheet Metal with Snips
1. Important: Alignment
The most important thing to remember when you cut sheet metal with snips is to fully insert the metal into the throat of the snips. This will allow for optimal cutting. Make sure that you use a sturdy workbench to support the metal.
2. Lay Out Your Pattern
Place the sheet metal on your work area and draw your pattern with a pencil or a straightedge.
- For curved cuts, use a piece of plastic molding to create an easy and adjustable template with the curve that you have in mind.
- Use two wooden blocks to clamp along the strip then use a plastic mold to bend and slide between the clamps. The molding should be about half an inch or less. You should have a setup that looks like the letter D.
- Then, loosen the clamps and adjust the wooden blocks to follow the shape of the curve that you need. Once you have the correct shape, place it on top of your sheet metal so you can trace it.
3. Start Cutting
Before you cut, make sure to wear your safety goggles and work gloves. Remember to open the snips wide as you begin each cut and place the edge of your sheet metal deeply into the throat or jaws of the snips.
- Align the blade of the snips with the pattern that you drew and keep it in contact with the sheet metal. Carefully squeeze the tin snips’ handles with one hand to start cutting. Repeat the process until you finish the cut.
Lastly, finish the cut by running a metal file along the edges of the metal. This will help clean up and remove burrs from the cut.
Cutting with a Metal Circular Saw
This probably the easiest technique to cut a metal sheet. You can accurately cut curved or straight lines even on thicker sheets. Just make sure you get the metal-cutting circular saw with a cold saw blade. These blades won’t leave any burrs on the sheet. Metal circular saws are a bit costly, so be sure you make the most of it with your projects.
How to Cut Sheet Metal with a Metal Circular Saw
1. Mark the metal sheet
Use a pencil to draw pattern where you want the metal sheet cut.
2. Clamp it
Be sure to clamp the metal sheet on the table it is placed to avoid unnecessary movements during cutting process.
3. Let the blade do the work
Metal circular saws are excellent tool for cutting metal. When cutting, let the blade do the work and don’t force it to go faster because it will surely damage the blade and will result in inaccurate cuts.
Deburring may not be needed because metal circular saws are known to have ready to work finish.
Cutting with a Hacksaw
You can also use a hacksaw to cut sheet metal however, you may find that you’re quite limited. It doesn’t have much of a turning radius and you can’t cut too deep because of its shape. We won’t say that this is the best way to cut sheet metal but it will work in certain applications.
If you plan to use a hacksaw for cutting sheet metal often, make sure to rub some wax along its blade to prolong the blade’s life. Your cuts will also be cleaner if you use a strip of masking tape and tape it on the top and bottom of the sheet.
How to Cut Sheet Metal with a Hacksaw
1. Draw Your Pattern
Using a pencil, draw a pattern that you can follow as you cut. If you want to cut straight lines, you can create a better guide or pattern by using a straightedge.
2. Oil the Blade
You can put a couple of drops of oil on the blade to improve the accuracy of the cut. This makes a big difference in the cut and will keep the blade from getting stuck or getting too hot. You can also use cutting fluid instead of oil.
3. Mount the Blade
Before you cut, make sure that the blade of your hacksaw is a metal-cutting blade. When you mount it, point the teeth facing away from you. This will allow the cuts to happen in a forward stroke and clear chips when you do back strokes.
4. Cut but Don’t Force
As you make your cuts, make sure not to force it or put too much pressure. You have to let the blade do the work. Always stay near the cutting guide that you drew to make sure that you maintain a straight cut.
Cutting with a Jigsaw
We also listed the handheld jigsaw as an effective tool to cut sheet metal. Make sure that your jigsaw has the proper metal-cutting blade. However, keep in mind that this tool is only suitable for short metal cuts.
If you want to achieve straight cuts using a jigsaw, clamp a straightedge on the sheet. This will guide the jigsaw’s footplate as you cut along the straight line. If you use a high-quality jigsaw, you will have a better turning radius and you can achieve consistent cuts.
How to Cut Sheet Metal with a Jigsaw
1. Weigh It Down
First, choose a flat working area and place your sheet metal. Keep it steady by putting a flat material like a plywood or other heavy objects to prevent it from moving as you cut. Sheet metal has a smooth surface so it tends to slip away if you cut using a jigsaw.
2. Mark the Sheet
Next, create a pattern of the shape or the curve that you want to cut using a permanent marker so that it’s highly visible. If you want to cut a straight line, you can use a ruler or any straight material like a piece of wood as a guide.
- You can drill some starter holes on the sheet using a drill blade before cutting all the way through if you want to make sure that you cut the perfect shape.
3. Cut Through the Sheet
Start cutting through the sheet following your guide or pattern. Do it slowly to stay within the guide and don’t push too hard.
- To avoid shredding, make sure that your sheet metal is tightly weighed down between the layers of plywood that you placed as instructed above.
- Be patient because it may take a while as you cut through the sheet. Do not rush the process when using a jigsaw because it could easily raise a lot of edge burrs if not done slowly.
Cutting with a Nibbler
Of course, this list would not be complete without the nibbler. This tool is so versatile and gives you a lot of control as you cut. Not many people would consider using a nibbler as the best way to cut sheet metal, but with the right technique, it can be quite efficient.
Basically, the nibbler would cut out punches from the metal in small pieces. You would have to repeat the process until you complete the cut. You can use either a handheld nibbler or a powered one.
How to Cut Sheet Metal with a Nibbler
1. Keep it Parallel
Using a nibbler to cut sheet metal is a lot similar to using a jigsaw. However, a nibbler doesn’t have the footplate of the jigsaw to keep in place so you have to make sure that you keep the nibbler’s body parallel to your sheet metal to keep it from binding.
2. Use Guides to Cut Straight Lines
To cut straight lines using a nibbler, you would have to use either a ready-made jig or template. You can also use a straightedge to keep the sheet in place as you cut.
3. Create a Starter Hole then Cut
If you need to start your cut in the middle of the sheet, you can use a drill to create a starter hole. This will make it easier for you to cut through. Now, you can start cutting through the sheet following the guide.
Cutting a sheet metal with a nibbler will almost always leave sharp edges and burrs. You would have to flatten or deburr it by using a hammer or you can polish the edges using a sander.
We’ve listed the above tools as some of the most efficient and most-preferred by handymen when it comes to cutting sheet metal. As always, you should consider the thickness of the material you are cutting and your level of comfort with the tool when choosing the right tool.
The key is to be consistent in the speed of cutting and to carefully follow the lines or patterns that you created as your guide as you cut. No matter which tool you choose to use, remember to be patient and cut slowly because too much pressure would cause inaccuracy on your cuts.