Snap-Off Knife

The snap-off principle is what makes it work. The blade is scored into segments; when the tip goes dull you snap the end off and a fresh sharp point appears. One blade holds seven or eight edges, which means there is never a reason to carry on with a blunt one. That is a safety point rather than a convenience one: a blunt blade skids off the material instead of cutting into it, and it goes in whatever direction you were pushing — usually towards the hand holding the work. Most knife injuries happen with dull blades.

The housing is plastic with a metal flute, and it is worth knowing which of those matters. The flute is the channel the blade slides in, and it is the part that determines whether the knife holds its blade rigidly. A blade in a worn or sloppy flute rocks under pressure, and a rocking blade snaps mid-cut. Having the flute in metal rather than moulded plastic is what keeps this knife accurate through many blades — the plastic housing around it is doing a much less demanding job.

It comes with one blade and takes Harden 570343 SK5 blades. If your work is heavy — pressing hard into thick material against a straightedge — the zinc alloy bodied version in this range is stiffer and worth the difference.

The buyers are shopfitters and installers, carpet and flooring fitters, packing and dispatch departments, signage makers, drylining contractors, offices and households, and hardware dealers, who sell these constantly.

Three habits. Extend one or two segments only — a long blade flexes and breaks under load, and a snapping blade sends a fragment somewhere. Cut away from yourself and never towards your other hand. And snap segments off with pliers or the snapper in the cap, holding the piece in a cloth, because a snapped segment is sharp on every edge.

And retract the blade every time you put it down. The commonest knife injury is reaching into a bag where an open one is lying. Ask us on WhatsApp for a price, singly or by the box.