9 Ways To Cut Sheet Metal

Article by Mark Trotta

Cutting out damaged sheet metal and trimming patch panels can be done in several ways. This article covers the pros and cons of the most popular methods, as well as a few less-known methods.

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Air Cut-off Tool

Also known as a "wiz wheel", an air-powered cut-off wheel with a 3" cutting wheel is the most often used tool for cutting metal off the body of a car.

cut-off wheel for automotive work

If you have a decent-size air compressor, cut-off wheels will cut sheet metal fairly quickly. Do not force the wheel to cut faster, it will put stress on the shaft bearing, overheat the tool, and possibly warp the metal. Let the air tool do it's job and move slowly along a marked-off line.

Other uses for a cut-off wheel include cutting off rusty bolts and muffler clamps. By changing the arbor, it becomes a die-grinder. The downside is they're noisy and throw off a shower of sparks.

Tin Snips

Another way to cut sheet metal is with Aviation Snips. They leave a clean cut, and are also useful for cutting copper and brass stock.

metal cutting snips

The only downside to Aviation snips is you need to buy three, a left, a right, and a straight. The handles are usually color coded to tell one from another at a glance.

Hand Nibblers

Hand-held nibblers work fine for smaller patches, but it takes considerable effort to cut through anything heavier than 20 or 22 gauge sheet metal.

Best Way To Cut Sheet Metal

Power Nibblers

If you do a lot of sheet metal work, consider a power nibbler.

Best Way To Cut Sheet Metal

Power nibblers save time, particularly on larger patches.

Electric Cutting Shears

Metal cutting shears are sort of like a pair of electric scissors. They are designed for cutting sheet-metal 14 gauge or thinner.

cutting metal with electric shears

They will cut straight lines smoothly, while removing a 1/4" or so of material where the jaws intersect. They will do slight curves, but don't handle ridges well.

Angle Grinder With Cutoff Disc

For the professional or serious home hobbyist, it's a real time saver to have a couple of 4-1/2" angle grinders, each fitted with a different type of disc. This saves time and hassle of switching back and forth from one to the other.

cut-off wheel for angle grinder

Read: Angle Grinder Attachments For Automotive Repair

Cutting speed of an angle grinder is dependant on amperage rating. A 13-amp motor will cut faster than a 7-amp motor. Note - make sure the blade is spinning "up" at the front of the cut or it will try to ride over the top.

Hand-Held Hack Saw

Before I ever owned an air tool or a power tool, I cut metal with a hacksaw. They come in many shapes and sizes, and their main drawback is they're slow and don't fit into tight spots well. You need to put more time and effort into it, but that always makes the finished product a little more personal.

9 Ways To Cut Sheet Metal

24T vs 32T Blade

To cut sheet metal, a 32T hacksaw blade is best. These are also best for cutting plastic. For the most efficient cut, mount the blade with the teeth facing forward.

Portable Band Saw

Originally marketed for cutting steel on job sites, portable band saws are very useful for small garage workshops. They cut metal fast and clean, and are quieter than abrasive saws. They work best with 1/4" thick or less metals.

Best Way To Cut Metal

Read: Milwaukee Portaband Review

The disadvantage of a portable band saw is most have a 5" opening, which restricts you to cutting pieces that are 5" width or less. So unless you have many small pieces to cut, it's really not the best way to cut sheet metal.

Horizontal Band Saw

A horizontal band saw is also great for repetitive cuts, but you're also limited by the neck width. Because they carry a high price tag, they're out of reach for the average DIYer.

Best Way To Cut Metal

Portable band saws can also be bench-mounted or stand-mounted. Many companies, including Swag Offroad, sell tables to convert portable band saws to horizontal table saws.

Best Way To Cut Metal

How I Cut Sheet Metal

On a large panel of sheet metal, I'll start with metal cutting shears to cut it into rough shape. Then I'll use hand nibblers and an angle grinder to trim it to exact shape.

I use a black marker to mark the cut, remembering to add about 1/8" or so to the line for trimming.

Notes and Cautions While Cutting Metal

Protect your hands from sharp edges - always wear gloves.

Clamp the piece of metal you need to cut in a vise securely.

Wear a face shield or safety glasses with side-protectors.

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