HAP40 (High Alloy Powdered) steel is a semi-stainless powder-metallurgy high-speed tool steel, it's edge retention exceeds anything possible with conventional steel, making it suitable for very abrasive timbers, glued laminates, engineered wood products etc.
Made at Yasugi Special Steel by blending metal powders and then heating them under intense pressure to just under melting point so that the atoms fuse without ever going through a liquid phase.
HAP40 requires great skill to forge; to produce a laminated blade from it by hand is a quite a feat, even for a master blacksmith like Uozumi san.
Rather than the traditional ura in the centre of the blade, these are ground fractionally hollow in their length, like an Ashley Iles chisel. The same principles apply, try to establish a small line of polish using as few strokes on the stone as you can, then only wipe off the burr on your finest stone, eking out the carefully ground hollow over many thousands of sharp edges. This style of blade will never need uradashi (tapping out) although you do need to be careful to keep the polish symmetrical left to right.
Pre-fitted white oak dai, very little fine tuning required.
Suitable for hardwoods, exotics, and even engineered wood / gluelam.
- Sole dimensions: 290 x 85mm
- RC 66-68
- Blade width: 65mm
- Cutting Width: 60mm