What is the best way to cut metal with a jigsaw?

When working with metal, having the right tools for the job is essential for achieving clean, precise cuts. One versatile tool used for cutting sheet metal is the jigsaw. Jigsaws are handheld power saws designed for making curved or irregular cuts in various materials, including thin to medium thickness metal sheets.

What types of metal can be cut with a jigsaw?

Jigsaws equipped with specialized metal cutting blades are capable of cutting through many thin metal materials up to about 1/8 inch thick. Some common metals that can be successfully cut using a jigsaw include:

• Aluminum sheet
• Copper sheet
• Galvanized steel sheet
• Stainless steel sheet
• Mild steel sheet
• Brass sheet
• Tin sheet

Thicker and harder metals like tool steel, cast iron, and heavier gauge sheet metals are typically too dense for a jigsaw to effectively cut through. For thicker metals, an abrasive cut-off saw or metal cutting bandsaw would be a better choice.

What types of jigsaw blades work best for cutting metal?

Choosing the right type of jigsaw blade is key to achieving clean cuts in metal. Look for blades specifically designed for cutting thin gauge metals. These blades have the following characteristics:

• Smaller teeth with a tooth pitch between 14 to 20 teeth per inch (TPI). More teeth help prevent fast wear when cutting metal.
• Coarse tooth geometry with large gullets for efficient chip removal
• Tooth tips made of durable high speed steel or tungsten carbide
• Optional cobalt or titanium coatings for added wear resistance
• Thinner blade profile to reduce blade deflection in denser materials

Standard wood-cutting jigsaw blades are too wide and have finer teeth that will wear out extremely quickly on metal. Using the wrong blade will give poor cutting performance and may damage the blade.

How to choose the right TPI for metal cutting blades

Metal cutting jigsaw blades typically have lower TPI counts compared to wood blades. Lower TPI blades are better for cutting thin sheet metals for a few reasons:

• Wider teeth are stronger and less prone to breaking when cutting dense metal
• Larger tooth gullets allow faster chip ejection
• Lower TPI makes for a smoother cutting action and reduced blade vibration

As a general guideline, choose blades with the following TPI for different metal thickness:

Metal Thickness	Recommended TPI
16-18 gauge (up to 1/16″)	14-18 TPI
20 gauge (up to 0.6″)	18-24 TPI

When in doubt, start with a blade on the lower end of the TPI range. Moving to a blade with slightly more TPI may provide a smoother cut on thinner materials.

Proper jigsaw technique for cutting sheet metal

In addition to having the right blade, proper jigsaw technique is equally important for controlling cutting through thin sheet metal:

• Secure the sheet firmly to prevent vibration. Clamp down the sheet if possible.
• Support the waste side of the sheet near the cut line to avoid tearing of the metal.
• Let the blade do the cutting using light downwards pressure. Don’t force the jigsaw through the cut.
• Cut slowly and steadily while maintaining blade speed. Cutting too fast risks deflection and poor cuts.
• Blow away metal chips frequently with compressed air to keep the cutline clear.
• Use cutting lubricant for reduced friction and cleaner cuts.

Rushing through cuts and forcing the saw leads to premature blade wear as well as less accurate cuts. Taking it slow allows the proper teeth cutting action.

How to cut straight lines in sheet metal with a jigsaw

While jigsaws excel at curved cuts, they can also execute straight cuts in sheet metal when guided properly. Here are some tips for straight line jigsaw cuts:

• Use a narrow blade with higher TPI for maximum straight line precision. A blade around 24 TPI works well.
• Align the edge of the jigsaw base plate parallel to cut line. Use a square as a guide if freehanding.
• Secure a sturdy straightedge clamped to the sheet as a saw guide. Run the base plate along the straightedge.
• Take it slow and steady, allowing the blade to cut smoothly without forcing.
• Support the waste side of the sheet near the blade to prevent tear out.
• Use a steel ruler as a permanent cut guide by clamping it down and cutting along its edge.

With good metal blades and proper guiding, straight line rip cuts up to a few feet long can be made with a jigsaw. For the very best straight line cutting precision, a portable bandsaw is better equipped for the task.

Cutting stacked sheets or sheet metal bundles

It’s possible to make cuts through multiple stacked thin sheet metal pieces up to about 1/4 inch total thickness. Follow these tips when jigsaw cutting sheet metal stacks:

• Use additional clamps to firmly secure the stacked sheets in order to resist vibration.
• Go slower through the cut to allow the blade time to penetrate each layer.
• If available, use a jigsaw with an orbital setting and turn it off for stack cutting. This reduces blade wandering.
• Consider taping stacked sheets together on the cut line side for a smoother cut.
• Take extra care supporting the cut off side to prevent binding and tearing of the lower sheets.

The more layers being cut, the more critical proper blade selection, workpiece securement, and cut rate control becomes. Cutting metal stacks taxes jigsaw blades significantly more than single sheets.

How to drill starter holes for interior jigsaw cuts

For internal cutout shapes in sheet metal, jigsaws require starter holes drilled along the cut line. The size of starter hole needed depends on the jigsaw blade shank diameter:

Jigsaw Blade Shank	Recommended Starter Hole Size
U-shank (1.3mm)	5/32 to 3/16 inch
T-shank (3.2mm)	1/4 inch

Drill starter holes about 2 inches apart along curved cutlines, and up to 4 inches apart on straight lines. Holes that are too far apart make it harder for the jigsaw to cut cleanly between them.

For tight interior cutout shapes, drilling starter holes at corners first allows angling the blade to start interior cuts. Make sure to deburr holes thoroughly so the blade doesn’t catch on edges during insertion.

Best jigsaw accessories for metal cutting

Certain jigsaw accessories can make metal cutting safer, easier, and provide cleaner cut results. Helpful accessories to have include:

• Fine toothed metal cutting blades – Having a range of TPI blades makes it easier to match the tooth pitch to the material thickness.
• Scrolling jigsaw blades – Tiny pin-end or spiral blades for tight curved cuts with minimal turning radius.
• Blade assortment packs – Sample different blade types and tooth configurations to find the optimal blade.
• Base plate edge guides – Aftermarket guides attach to the base plate for steadier straight line cutting.
• Cutting lubricants – Reduces friction and helps blades run cooler when cutting.
• Fret saw – For starter holes, a hand-powered fret saw can achieve tighter turning radiuses.

Investing in the right accessories makes jigsaw metal cutting much more efficient. Quick access to different TPI blades for the material at hand is highly recommended.

How to cut circles and holes with a jigsaw

Cutting circular holes or shapes in sheet metal can be accomplished using a jigsaw with a scroll cutting blade installed. Here are some tips for circular jigsaw cuts:

• Use a fine tooth scroll blade, like 16 TPI pin-end, for tight radius cuts.
• Drill a starter hole at the center point of the desired circular cutout.
• Insert the blade through the starter hole vertically before angling to the cut direction.
• Pivot the base plate around the starter hole while cutting a gradual curve.
• Maintain an even curve cut by adjusting the blade angle and moderate feed rate.
• For larger holes, scroll from the perimeter and work back to the center.

It takes practice to consistently cut accurate circles with a jigsaw freehand. Various circle cutting jigs are available to guide the blade for more precision.

Cutting tips for specific metals

Certain metals have characteristics requiring special considerations when cutting with a jigsaw:

• Aluminum – Use spray lubricant and slow feed rate for clean cuts. Reduce tear out on back by clamping sacrificial wood underneath.
• Stainless steel – Harder material requires more blade teeth. Keep TPI on the higher side of the range for thickness.
• Copper – Soft material tends to load up blade teeth with residue. Periodically clean blade with abrasive pad while cutting.
• Galvanized steel – Zinc coating builds up rapidly on blade. Cut slowly and replace blade more frequently to maintain cut quality.

With any metal, make sample cuts on scraps first to determine optimal blade TPI and cutting speed before cutting into project materials.

How to reduce burrs when jigsaw cutting metal

The downside of jigsaw cutting thin sheet metal is that it often produces burrs along the cut edge. Here are some methods to minimize burrs:

• Use wider TPI blade to reduce teeth skipping that can cause burring.
• Cut slowly and avoid forcing blade through material to prevent deflection.
• Support the waste side of the sheet near the cut to eliminate tear-out burrs.
• Place a sacrificial wood backer underneath to absorb some of the cutting force.
• Add a finishing operation such as filing, sanding, or deburring to refined edges.

For thicker metal sheets, a cold saw or band saw will typically produce cleaner, burr-free edges. But for thin gauges, jigsaws can make the cut with the right blade and technique.

Safety tips for cutting sheet metal with a jigsaw

Working with jigsaws on metal comes with certain safety considerations:

• Wear eye protection to guard against flying chips and particles.
• Use hearing protection, as cutting metal is louder than wood materials.
• Support sheet metal adequately and secure with clamps to prevent vibration.
• Keep fingers safely clear of the blade while cutting and during insertions.
• Avoid awkward hand positions and maintain proper footing and balance.
• Beware of sharp edges after cutting and use gloves when handling sheet metal.

The safety precautions taken when using any power saw are greatly amplified when cutting harder, denser metal materials. Operate carefully within the jigsaw’s capabilities to complete metal cutting tasks successfully and safely.

Conclusion

With the right jigsaw blade selection and proper cutting technique, thin gauge sheet metal can be cut effectively with a jigsaw. Choosing blades designed specifically for cutting softer metal sheets is critical for clean cuts. Supporting the workpiece rigidly, going slow, and using lubricant also improves results when jigsaw cutting metals. While requiring more care and skill than cutting wood, jigsaws equipped for metal are up to the task for projects using thin gauge metals.