DeWalt 18-Gauge Shear Attachment

Why I reached for a shear attachment instead of snips

I spend a lot of time trimming roofing, duct, and assorted sheet goods on jobs where hauling a dedicated power shear isn’t practical. That’s where a compact add‑on like this DeWalt shear attachment earns its keep. It snaps into a standard 1/4-inch hex chuck and turns a drill or impact driver into a powered shear capable of slicing up to 18‑gauge mild steel. In a backpack or tool tote, it’s a small space trade for a big bump in speed and comfort over manual snips.

After several projects—roof repairs with corrugated panels, ductwork alterations, and a handful of plastic and vinyl siding cuts—I’ve got a solid feel for where this attachment shines and where it doesn’t.

Setup and first impressions

Installation is as simple as it should be: insert the 1/4-inch shank into a drill or impact driver, tighten, and go. The head swivels 360 degrees, which matters more than it sounds; with the throat oriented correctly, you can steer along lines that would otherwise force you into awkward body positions. The build is all business—steel head, a compact housing, and enough heft to feel stable without tipping a drill forward excessively. On a mid-size 20V drill the overall balance is very workable.

I tried it on both a variable-speed drill and an impact driver. It runs on either, but I strongly prefer a two-speed drill in low gear. The continuous torque makes the cut smoother and noticeably quieter than the staccato of an impact, and it’s easier to modulate speed right at the edge of chatter.

Cutting performance on metal

For straight lines and gentle curves, this thing moves. On typical roofing stock (think 26–29 gauge) it zips along quickly while leaving a predictable kerf. Up near the top of its capacity on 18‑gauge mild steel, you feel the tool working—feed rate slows, but it still tracks fine if you keep the work well supported and maintain a steady pace.

A key point: this is a single‑cut shear. It displaces material to one side as it cuts, leaving one edge slightly wavy with a raised curl. That edge can’t be pressed truly flat again. On panels where the edge is hidden under trim or overlap, it’s a non-issue. If you need a dead-flat finish on both sides, double‑cut shears (which remove a thin strip down the center) leave a cleaner edge at the expense of a sacrificial ribbon of waste. For most exterior metal work, I’m happy with the single‑cut tradeoff given the speed.

Curves are possible, but not tight. Think gradual arcs and soft S‑curves. The throat length and jaw geometry limit how sharply you can turn, and if you try to yank it around a tight corner you’ll deform the work. For intricate shapes, a nibbler is still the right tool, especially on interior cutouts.

Corrugated and ribbed panels: where it works, where it doesn’t

On corrugated roofing, the shear attachment excels going along the flats in the direction of the corrugation. The cut is fast, with less burr than using snips, and it’s easier to hold a straight line. Across the ribs is a different story. The nose gets hung up as you climb each rib, and the jaws don’t like the changing angles. For cross-corrugation cuts, I switch to a nibbler or a track-guided saw with a metal blade. If you’re doing diagonal cuts across ribbed siding, plan accordingly—the length of the head will bottom out against the ribs and stall your progress.

Beyond metal: plastics, vinyl, rubber, and mesh

One nice surprise is how versatile the shear is on non-metal sheet goods. It cuts PVC panels, vinyl siding, and rubber mats cleanly without melting, and it won’t spray plastic dust the way a saw does. On expanded metal and steel mesh, you need to keep the mesh supported close to the cut and move slowly; the staggered strands can twist into the throat if you rush. For asphalt shingles, it slices, though you’ll gum up the jaws if the day is hot—wipe down more frequently and expect more resistance.

Maneuverability and ergonomics

The 360° swivel head is the quiet hero here. Being able to rotate the head so the jaw opening follows your line keeps the drill body in a comfortable orientation—crucial when you’re cutting long panels at shoulder height or on a roof. The attachment adds some weight forward, but not so much that it fatigues your wrist in short sessions. For longer cuts, I rest the drill’s side on the sheet and let the tool’s nose guide along a straightedge or chalk line.

One ergonomic caveat: because the head is relatively long, cutting inside tight cavities (between studs, against a wall return, or in a narrow downspout) isn’t its strength. There are compact, purpose-built electric shears that fit better in cramped spaces.

Edge quality and cleanup

The cut edge on metal is generally clean but slightly wavy on one side. Burrs are minimal compared to abrasive methods. I usually run a quick pass with a deburring tool or a file where the edge will be handled. On plastics and vinyl, edges are very clean with no burning or chipping. Because this isn’t a nibbler, you don’t end up with hundreds of little crescent-shaped chips all over the ground—a small but appreciated benefit when working on a finished surface.

Practical tips for best results

• Use a drill in low gear with consistent feed for the smoothest cut.
• Keep the lower jaw shoe flat on the work; twisting induces chatter and distortion.
• For interior cutouts, drill a starter hole large enough for the jaw to enter.
• Support thin material close to the cut line to prevent flex and oil-canning.
• Rotate the head so the waste side curls away from the panel you’re keeping.
• Mark both sides of heavier gauge sheet—visibility can be tricky from above.
• Wear gloves; the waste side of a single‑cut edge is sharp and wavy.

Durability and maintenance

The steel head feels robust, and after a mix of steel and vinyl work the cutting edges still bite well. As with all shears, longevity depends on what you feed it. Stay within the 18‑gauge capacity for mild steel, and be conservative on harder alloys. Wipe down the jaws after cutting asphalt products or anything adhesive-laden. If you use it frequently on galvanized sheet, periodic light oil helps stave off corrosion and keeps the action smooth.

Compatibility and storage

The 1/4-inch hex shank makes this essentially brand-agnostic. I ran it on a DeWalt 20V drill and an impact from another brand without any fit issues. Because it’s an attachment, it shares the batteries you already own—one less charger on the bench. It’s also small enough to live in a drill case or a pouch; I keep mine in a soft sleeve so it doesn’t nick other tools.

Value and use case

There are faster, cleaner-cutting options out there—dedicated double‑cut shears and high-end nibblers are fantastic but cost and bulk add up. The appeal of this attachment is how quickly it turns a tool you already own into a capable shear for sheet goods. For roofing, siding, duct transitions, and general shop use, it punches above its size and price. If your work is mostly light-gauge steel or mixed materials, it’s a smart addition. If you constantly cut across corrugations, do a lot of interior cutouts, or demand perfectly flat edges, budget for a nibbler or double‑cut shear alongside it.

Who it’s for

• Remodelers and roofers who need fast straight cuts on panel goods
• HVAC techs trimming duct and plenums on site
• DIYers building sheds, fencing, or metal projects with lighter gauges
• Anyone who wants cleaner cuts on plastics and vinyl without the mess of sawdust or melted edges

If your projects skew toward intricate shapes, tight radii, or heavy-gauge or stainless work, look elsewhere.

Recommendation

I recommend the DeWalt shear attachment for users who already carry a drill or impact driver and need a compact, versatile way to cut sheet goods up to 18‑gauge. It’s quick on straight lines, controllable on gentle curves, and surprisingly handy on plastics and vinyl. Its limitations are real—single‑cut edges aren’t dead flat, tight turns are off the table, and it’s not the right choice for cross-corrugation cuts—but within its lane it performs reliably and saves time. For the price and the space it occupies in a kit, it’s an easy tool to justify.