Miki-Powder metal HSS.

The blades in these planes feature a special Powder Metal High Speed Steel edge bonded to a soft iron backing for use with the most demanding, abrasive materials such as silica rich solid timber, extremely hard woods and man made materials.

But what does "Powder Metal" really mean?

When making steel, it is most commonly made in a large pot rather like a soup. Iron makes up most of the composition, carbon is also added and depending on the steel being made, other elements and compounds are added. Because steel is finicky at times, there are limits as to what can be added before the steel stops being cooperative. And more often than not, compromises must be made when adding to the steel. Add some chromium and the blade resists rust and stays sharp for longer, but might become brittle. Add tungsten, and the blade can be harder and more wear resistant, but the steel's grain becomes bigger, and can't take as keen an edge. And so on and so on. There's always a bit of juggling going on, and steel makers are always trying to find a good balance for a particular steel and what it's intended to do.

However, taking these ingredients, and creating a very fine powder with them, and forming them as one homogeneous mass under great pressure and heat, many of the limits found when creating steel alloys can be circumvented, and as a result, Power Metal steels can be created to offer properties that more conventional steels are unable to attain.

In this case, the Powder Metal is a special High Speed Steel created by Hitachi metals called 'HAP 40', resulting in what is, for all intents and purposes, Super High Speed Steel.

Compared to regular SKH-51/M2 grade HSS, Hitachi's HAP 40 offers improved edge life, increased toughness and the ability to take a finer, sharper edge. Impressive when you consider how much tougher and long lasting even regular High speed steel is when compared to traditional style carbon and alloy steels.

Of course, this added toughness also translates to a little more difficulty actually sharpening the edge, but thanks to a unique blade back design developed by Tsunesaburo, the problems of sharpening these 'super blades' can be significantly reduced.



By creating what is called an 'uradashifuyouh' back, only a very small area at the very tip of the blade requires flattening and honing. A very slight curve for length along the back helps maintain that very small area for the (long) life of the blade, making sharpening these blades considerably easier and completely eliminates the need for 'tapping out' the edge as might be required of a more conventionally shaped kanna blade.

(We also highly recommend the Sigma Power Select II stones for these planes, making sharpening them a breeze!) 

Available in 2 styles, the 'clipped corner' blades feature the unique back treatment Uradashifuyoh for easy sharpening. The 'round top' blades use a more conventional back treatment.

If you find that your plane's blades are not lasting as long as you might wish, or find yourself working with especially abrasive materials, then one of these 'Miki' planes may be the solution for you.



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