Jorgensen No.4 & No.5 Planer Blade — Replacement for No.4/No.5 Planes | 9CrWMn O1 Steel, 3mm

Jorgensen No4 and No5 Planer Blade: Precision, Durability, and Quick Replacement

Designed to fit Jorgensen No4 Smooth Plane and No5 Jack Plane, this blade leverages 9CrWMn steel, a professional-grade material in the O1 family, chosen for clean cuts and solid edge retention over multiple sessions. The 3 mm thickness contributes to a stable cutting geometry that helps you maintain consistent shavings, even when working with varying grain and stock thickness.

What makes this blade stand out

Hard-wearing, sharp, and reliable, the blade balances aggressive cutting with controlled feed. The high hardness range of HRC 62–64 supports longer periods between sharpenings while preserving a crisp, even surface you expect from a well-tuned plane.

• Professional-grade blade material reduces wear during long planing tasks.
• Edge retention supports repeated sharpening while preserving cutting geometry.

In practical use, woodworkers notice the difference during stock preparation, panel flattening, and fine joinery. The blade is designed for quick replacement on compatible planes, minimizing downtime and letting you focus on shaping, smoothing, and precise fitting. The 3 mm thickness helps maintain stable cut flow, contributing to predictable shaving thickness and surface feel across different woods.

• Easy, tool-free replacement on No4 Smooth Plane and No5 Jack Plane.
• Consistent performance across a range of hardwoods and softwoods with careful tuning.

Real-world scenarios include preparing faces before joinery, refining edges for tight seams, and removing mill marks from rough stock. The blade’s design supports precise control and repeatability, which is especially valuable during longer sessions or when working on multiple components in a project.

Material quality and grind matter: the 9CrWMn steel delivers a balanced blend of hardness and toughness, with a finely honed edge. Thoughtful heat treatment and geometry help maintain resilience during heavy planing while delivering clean shavings. The 3 mm thickness resists deflection, making the blade reliable when working near end grain or dense timber.

Quick care and maintenance can extend edge life: wipe away resin after use, keep the blade dry, and perform a light touch-up with honing oil as needed. Store with protective coverage to prevent chips and keep the edge ready for your next project.

Bottom line

This Jorgensen blade offers a balance of sharpness, hardness, and ease of use tailored for No4 and No5 planes. It presents a practical option for woodworkers seeking reliable edge life and consistent planing results. Use it as a high-performance enhancement in your toolkit to explore what your No4 or No5 plane can achieve, while keeping expectations grounded in real-world use.