Choosing a jigsaw for metal

I spent most of the 1990s cutting thin sheet metal on job sites with old, heavy corded tools. Most woodworkers think a jigsaw is only for plywood or MDF. They are wrong. If you need to cut a hole in a steel backsplash or trim an aluminum flashing strip, you can use your jigsaw. You just cannot use it the same way you use it for oak.

Blade selection and TPI

The blade does most of the work here. Wood blades have large teeth that will snap instantly against steel. You need a high TPI count to handle metal safely. Look for at least 24 TPI for thin sheets.

Thin blades are better. A fine-tooth blade prevents the tool from vibrating too much when it hits hard surfaces. If you use a coarse wood blade on a 1/8 inch steel plate, you will ruin the teeth in seconds.

Speed matters too. Slow your tool down significantly. High speeds create heat that ruins the temper of the metal and the blade itself.

Managing heat and friction

Heat is your enemy. Metal gets hot fast during a cut. If the blade turns blue, it is dead.

Use cutting oil. Apply a drop of 3-in-One oil or even standard WD-40 directly to the cut line as you work. This keeps the temperature down and helps the teeth slide through the material without seizing up.

Clamp your workpiece tightly. Metal vibrates like crazy when it isn't secured to a heavy workbench. That vibration causes "chatter," which leads to jagged edges and broken blades.

Tool settings and stability

Switch to orbital mode is a mistake. Most jigsaws have an orbital action setting that moves the blade in a circle to speed up wood cutting. Turn this setting off for metal work.

You want a straight stroke. A pendulum action will kick the blade out of the groove and potentially throw a shard of metal across your shop. Set the machine to its lowest orbital setting or zero.

Check your shoe. The baseplate must be flat against the metal. If the tool wobbles, you lose control of the cut immediately.

Safety gear for sparks

Metal cutting is messy. It creates hot chips and fine dust.

Wear eye protection always. I have seen small metal slivers fly up when a blade binds in a thick aluminum plate. A pair of wrap-around safety glasses is the bare minimum requirement for this task.

Earplugs are necessary too. The high-pitched screech of metal being cut by a jigsaw is much louder and more piercing than the low thud of cutting pine. Use rated protection to save your hearing over long sessions.

Frequently asked questions

Can I cut stainless steel with a standard jigsaw?

It is difficult. Stainless steel work-hardens very quickly, meaning it gets tougher as you cut it. You must use specialized cobalt blades and extremely slow speeds to avoid ruining the tool or the material.

How do I stop the metal from bending?

Support the material properly. Use a sacrificial piece of scrap wood underneath the metal to provide a solid backing for the blade to push against. This prevents the thin sheet from fluttering during the cut.

Will my jigsaw motor burn out?

It is unlikely if you are careful. The motor works harder because you must run at lower speeds, but as long as you do not force the tool through thick steel, it will hold up fine. Keep the tool moving to prevent heat buildup in the housing.