15 · Power Tools

Metal Shears

Also called Power shears · Nibbler · Sheet metal shears

Powered shears that cut sheet metal cleanly without the heat, sparks or distortion of a grinder.

Electric (corded)

Overview

Metal shears cut sheet by slicing it between two blades, the way scissors do, instead of burning through it.

That matters on coated and galvanised sheet: there is no heat, so the coating next to the cut is not damaged, and the edge comes out clean enough to handle.

They are used on roofing and cladding sheet, ducting, gutters and flashing, and will follow a curve as well as a straight line.

Check the thickness rating before cutting. Pushing shears past their capacity damages the blades.

Best uses

Roofing and cladding sheet
Ducting, gutters and flashing
Galvanised and coated sheet where heat would damage the coating
Curved cuts in sheet

Not suited for

Thick plate or bar beyond the rated capacity
Hardened steel

Troubleshooting

Find a symptom

The shears stall in the cut

Checks to try, in order

The material is thicker or harder than the tool's rating.
Check the blades for nicks and wear.
Slow down and let the tool work at its own pace.

Reference draft — always follow the manufacturer’s manual.

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The cut edge tears or distorts

Checks to try, in order

Keep the tool square to the sheet.
Support the sheet close to the cut so it cannot flex.

Reference draft — always follow the manufacturer’s manual.

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Tool won't switch onShared · Electric (corded)

Likely causes

Tripped GFCI or breaker
Lock-off button
Damaged cord
Dead outlet

Checks to try, in order

Check the outlet works and reset any GFCI / RCD that has tripped.
Release the lock-off button or safety switch before squeezing the trigger.
Inspect the cord and extension lead for cuts, crushed sections or damaged plugs.
If running from a generator, make sure it's running and its breaker hasn't tripped.

A damaged cord or plug means the tool is out of service. Tag it and return it — never tape a cord.

Reference draft — always follow the manufacturer’s manual.

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Keeps tripping the breakerShared · Electric (corded)

Likely causes

Circuit overloaded
Undersized extension cord
Blunt accessory

Checks to try, in order

Plug into a circuit with nothing else heavy running on it.
Use a shorter, heavier extension cord. Long, thin cords starve the motor and trip breakers.
Don't force the tool — a dull bit, blade or disc makes the motor draw more current.

Reference draft — always follow the manufacturer’s manual.

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Overheating, burning smell or heavy sparkingShared · Electric (corded)

Checks to try, in order

Stop and unplug the tool.
Check the motor vents aren't blocked with dust.
Let it cool, fit a sharp accessory and let the tool's weight do the work.

Heavy sparking from the vents or a burning smell that returns points to worn brushes or a failing motor — workshop only.

Reference draft — always follow the manufacturer’s manual.

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Safety

Cut sheet edges are razor sharp. Gloves, and handle the offcut carefully.
Eye protection — swarf flies off the blades.

For electric (corded)

Inspect the cord and plug before every use. Use a GFCI/RCD outdoors or near water.
Unplug before changing blades, bits, discs or pads.
Wear eye protection, and a dust mask when cutting, grinding or sanding masonry.