10Pcs 25x125mm Knife Blades

A standard snap-off blade is 18mm wide and thinner. At 25 by 125 and 0.7mm thick these are substantially larger in every direction, and thickness is the important one. A thin blade extended more than a segment or two flexes under heavy pressure, wanders off a straightedge and eventually snaps mid-cut. Seven tenths of a millimetre is stiff enough to stay where you point it, which is what makes these the blades for insulation board, thick card and packaging, carpet and underlay, plasterboard, dense foam and heavy sheet materials. They also reach deeper, so thick material can be cut in one pass rather than scored from both sides.

The steel is SK5 — a Japanese high carbon tool steel at roughly 0.8 to 0.9 percent carbon, hardened and tempered. The high carbon content is what allows a high hardness, and hardness gives both a keen edge and the ability to hold it. On thick abrasive material like mineral wool insulation or dense board, edge retention is what decides how many metres you cut per segment.

Seven segments per blade, so each one gives seven fresh points before it is used up. They fit the 25mm heavy duty knife in this range.

The buyers are insulation and drylining contractors, carpet and flooring fitters, packing and crating departments, shopfitters, roofing contractors, upholsterers, and hardware dealers supplying trades cutting thick material.

Three habits, and they matter more with a large blade. Extend only as much as the material depth requires — even a 0.7mm blade flexes when most of it is hanging out, and a large blade breaking under load throws a substantial piece of sharp steel.

Snap segments off with pliers or the knife's cap snapper, holding the piece in a cloth. A 25mm segment is not a sliver; it is a sizeable blade in its own right and it is sharp on every edge.

And collect used segments in a tin or taped container rather than a bin, since loose blades cut whoever handles the waste. Message us on WhatsApp for a price.