Veritas Replacement Blade for Low Angle Jack Plane, 25º Bevel, PM-V11
This Veritas Lapped 25° blade, 2-1/4" wide by 3/16" (0.187") thick, is for the Veritas Bevel Up Low Angle jack Plane, made from PM-V11 tool steel.
Veritas Lapped Plane Blades
Lapping the blade is the critical first step when preparing a blade for use. The reason for this may not be obvious until you understand that the sharpness of a cutting edge is determined by the intersection of two surfaces (the bevel and the opposing face), and that the smoother and flatter these two surfaces are, the keener the intersection. The lapping process can be an arduous task, especially when dealing with today's hard tool steels. This process, when done by hand, involves numerous steps and will require a good deal of your time to achieve an acceptable working surface.
To reduce the time and effort you spend on this activity, Veritas now laps their PM-V11 plane blades on the face (non-bevel side) to a flatness tolerance of ±0.0002" or better over the working surface, and with an average roughness surface finish of 5 microinches (0.000005") or better. Because you begin with a blade that has already been lapped flat, your efforts may now be focused on providing the final polish to the face and honing the micro-bevel – tasks that require significantly less time and effort than lapping the blade face.
On Veritas regular and bevel-up plane blades, the working surface is the section of the face that extends from about 1/8" below the bottom of the screw slot to the cutting edge; on shoulder and bullnose plane blades, it is the widest section of the face from the shoulder to the cutting edge. Average roughness (Ra) measures the height variations in the surface over a given area and then provides an average roughness
value to represent the surface finish – the lower the value, the better the finish.
Lapped 38° and 50° blades are also available for the Veritas Low Angle Jack Plane, as well as a toothed A2 blade for working difficult grain.