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18mm Snap-Off Blade Utility Knife
Official Hyde specifications
Dimensions
18 mm
Product type
Utility Knife, Blade
Retractable blade with 2-piece positive lock
1 blade included
High-impact polystyrene
PRODUCT FIT · IS THIS THE RIGHT TOOL?Straight answers. If it's the wrong tool for your job, we'll say so.
The guidance below describes applications and limitations. For a match to your particular job or an existing tool, ask us to confirm fit.
Wet wallpaper, vinyl graphics, masking film, and any cut that must follow a tight curve or hold fine registration — the 18mm blade is too stiff and too wide to steer that work, which belongs to the 9mm snap-offs (42036/42045).
Leveraged cutting into wood and cold-weather abuse, where a thin snap segment will crack and a backed trapezoid blade (42020/42083) is the right tool.
Carton opening where a written safety program governs the building — that is the exposure-limited Switchblades' job (42060/42065).
And it does not score brittle sheet: acrylic and laminate crack under a slicing blade; the 45730 plastic cutter removes a chip instead.
Match extension to the job, and lock what you extend
Short extension for pressure work and box scoring; long extension only for the full-depth foam pass, and only with the positive lock engaged. The lock is a two-motion deliberate act — position, then lock — so use it; an unlocked blade run out at depth is the classic way to snap a segment mid-cut. Snap at the drag, not at the visible dullness. By the time a wide blade looks dull it has been dragging for several cuts; renew at the first change in how the cut parts. Snap safely. Cover the blade break line — the snapper cap, pliers with a rag, or the dispenser's snap feature — and snap away from your body; an 18mm segment is a stiff, sharp shard and it can flick. Keep the used segments contained — snapped blades are the sharpest waste a jobsite makes; the 9mm 42356 dispenser (sibling line member) is the family's built-in sharps answer, and even the 18mm operator should have a dedicated sharps container, never a loose trash bag. Carbon steel wants to stay dry — wipe the blade after wet or adhesive work; a fresh segment is always seconds away, but the installed one will bloom rust if left wet.
Asked before buying
BUYER QUESTIONS, ANSWERED BEFORE YOU ORDER
Why 18mm instead of 9mm?
Stiffness. The wider blade resists the cantilever flex that makes a narrow blade wander and snap under pressure, so it scores drywall, cuts rigid foam, and takes real hand force — where the 9mm is for precision and curves.
Why only 8 points when the 9mm has 13?
Each 18mm segment is longer, so the same blade divides into fewer, coarser renewals — matched to the coarser work.
What is the positive lock for?
Fixing a run-out blade so it cannot creep under load — essential for the one job where you extend far, the full-depth pass through foam board.
How do I snap a segment safely?
Cover the break line (snapper cap, pliers-and-rag, or the dispenser feature), snap away from your body, and contain the shard — snapped segments are the sharpest waste on the job.
Will the blade rust?
It is carbon steel — wipe it dry after wet work; and since a fresh segment is always a snap away, a rusted installed segment is no crisis.
