Power Shears & Guillotine Cutters

Power shears cut sheet metal, plastic, rubber and paper with a straight blade that drops with huge force. Squaring shears in sheet metal shops and guillotine cutters in print shops can amputate fingers and hands in an instant. Safeguarding the cutting line, the hold-downs and the controls prevents most of these injuries.

• General Industry
• Sheet Metal
• Print & Packaging

How these machines work

• A power shear (also called a squaring shear or guillotine shear) holds a sheet on a table, clamps it with hold-down clamps, and drops a long upper blade against a fixed lower blade to cut it. The cut is across the width of the sheet.
• Drives are hydraulic, mechanical or pneumatic. The operator starts the stroke with a foot pedal, buttons or a two-hand control.
• A back gauge positions the sheet for the cut. Many machines have a front sheet support and a CNC back gauge.
• Paper cutters and guillotines work in the same way with a long blade and a clamp, and some are large, powered machines for books and packaging.
• Rotary shears, slitters and strip cutters are related machines with their own guarding needs. See Mechanical Power Presses, Press Brakes and Power Shears & Nibblers.

Main hazards

• Amputation at the point of operation: hands under or between the blade and hold-downs when the stroke begins. This is the main danger.
• Pinch points at the hold-down clamps, the back gauge and the sheet support.
• Accidental activation: stepping on an unguarded foot pedal or bumping a control.
• Repeat strokes: a malfunction can cycle the blade again.
• Sharp edges: cut sheet and scrap edges slice hands and arms. See Tin Snips & Metal Shears.
• Handling large sheets: heavy or awkward sheets, pinching and strain. See Lifting & Ergonomics.
• Blade changes and maintenance: sharp, heavy blades and stored energy.
• Noise and hydraulic leaks. See Noise.

Safeguarding

OSHA requires machine guarding for hazards like these (29 CFR 1910.212), and the consensus standard for shears and similar machines is ANSI B11.4. See Machine Guarding and Safeguarding Devices. Common protections:

• Fixed barrier guards or finger guards across the front of the cutting line, with openings small enough to keep fingers out of the blade, while letting the sheet through. The openings are limited by distance from the blade (the closer to the danger point, the smaller the opening).
• Hold-down clamps and pressure bars that press the sheet before the blade comes down, with guards so fingers can’t be caught between the clamp and the sheet.
• Light curtains or presence-sensing devices in front of the blade that stop the stroke if the beam is broken. They must be at a safe distance based on the machine’s stopping time.
• Two-hand controls placed far enough away so hands can’t reach the blade before the stroke ends, and designed so that one hand can’t operate both buttons.
• Foot pedal guards (covers or shields) so that the pedal can’t be hit accidentally, and a foot switch that works only when the safeguards are in place. Foot-operated controls are usually used only with other guarding.
• Back guarding or fencing to keep people from reaching in from behind the machine, and interlocks on access doors.
• Emergency stop buttons within easy reach.
• Anti-repeat and single-stroke controls so the blade can’t cycle more than once per command.

Safe operating practices

• Only trained, authorized operators run shears. Read the manual and know the capacity, controls and emergency stop. See Training Requirements.
• Inspect before use: check that guards, hold-downs, light curtains, gauges, foot pedal covers and emergency stops work. Don’t use a machine with missing guards. Report defects and tag out the machine.
• Check the material and the blade gap. Don’t cut thicker, harder or longer material than the machine is rated for, and use the right blade clearance for the material.
• Handle sheets carefully. Use gloves rated for sharp edges, cut-resistant sleeves and safety glasses. See Hand Protection, Cut-Resistant Sleeves & Arm Protection and Eye & Face Protection.
• Use sheet supports and a helper for large sheets, and have the helper stay clear of the blade and the hold-down area. Make sure only one person controls the machine and the helper keeps hands away.
• Position the sheet with the back gauge or marks, and keep hands outside the guard. Use tools or a push stick for small pieces and never feed pieces too small to hold safely.
• Keep the area clear: remove scrap and offcuts with a tool or a brush when the machine is stopped, and keep the floor clean of oil. See Slips, Trips & Falls.
• Leave the controls alone when someone else is feeding, and don’t leave the machine running unattended.

• Don’t tie down or bypass the foot pedal, buttons or light curtain.
• Don’t reach across the machine or under the blade to retrieve a piece.
• Don’t wear loose clothing, jewelry or long loose hair near moving parts.
• Don’t stack material on the machine bed, and don’t lean on the table while the machine is on.

Blade changes, adjustment and maintenance

• Lock out and tag out the machine, release hydraulic or air pressure and stored energy, and block the ram or blade so it can’t drop, before any blade change, adjustment or cleaning under the blade. See Lockout/Tagout and Blocking & Cribbing.
• Blades are heavy and razor sharp. Use proper lifting aids, blade handling tools and cut-resistant gloves, and keep blades in guards when stored.
• Follow the maker’s steps for blade gap and torque. A badly set blade can crack.
• Service hydraulic and pneumatic systems only when depressurized, and watch for fluid injection hazards. See Hydraulic Power Tools.
• Inspect and test the clutch, brake and safety controls regularly, with records, and don’t treat blade work as minor servicing. See Minor Servicing & Alternative Energy Control.

Employer responsibilities

• Provide guards and devices that protect every operator and helper, and make sure they are used and kept working.
• Train and supervise workers, enforce lockout and keep inspection records.
• Investigate near misses and injuries, fix the root causes and check older machines that lack modern guarding. See Incident Investigation.
• OSHA’s emphasis on amputation hazards in manufacturing means shears draw attention. See OSHA Emphasis Programs.

Shear safety checklist

• Front and back guards, hold-downs and light curtains in place and tested
• Foot pedal covered; two-hand controls or other devices work; emergency stop in reach
• Material within the machine’s rated thickness and length
• Operators trained, wearing cut-resistant gloves and sleeves and safety glasses
• Hands stay outside the guard; helpers stay clear of the blade
• Machine locked out and the blade blocked for changes, adjustments and cleaning

Last updated: October 4, 2026