sharp/dull blade drawing Knight high carbon steel small map
Finest abrasives.
Microbevels front and back.
Use a jig.
Copyright (c) 2002-15, Brent Beach

Test Summary

A high carbon steel (O1) blade, supplied with a Knight Tool Works smoother.

Better than most high carbon steel blades.

Cryogenic treatment affects the internal structure of the steel, depending on the type of steel. Some doubt that it can have an effect on O1 steel. Some claim that it is a big help for A2 steel. In my tests, this is some of the best O1 steel, so it seems to have helped a bit. See the tests of A2 steel irons.

Knight Irons

Steve Knight makes wooden planes in which he uses 1/4" thick O1 steel irons. These irons are appropriate only for this model of plane, not for Stanley style planes.

These blades receive a cryogenic treatment. At one time, Steve's web site discussed the process, but it no longer seems to. He does not say whether his current blades are cryogenically treated or not.

The Test

April 14, 2002.

As with all my other tests, I honed three front and back bevels using 15, 5, and 0.5 micron 3M micro abrasive paper.

This iron can only be tested in a Knight plane. My Knight smoother has a 60 degree bedding angle. Typically, irons bedded at 60 degrees wear faster than irons bedded at 45 degrees. It is probably because with a high bedding angle the plane is taking more of a scraping action than a cutting action.

The front bevel, 200 X magnification, after the 0.5 micron paper.

These short thick irons are difficult to sharpen, and difficult to position under the microscope. Perhaps if all irons were this shape, I would have developed more suitable jigs. Having now done the Mujingfang blade, about the same length but only about half as thick, I might be able to do a better job taking pictures of Knight irons.

The front bevel, 200 X magnification, after 100 passes along 4 foot douglas-fir board.

Very narrow wear bevel, about 4 pixels wide, with good edge quality.

100 passes
The front bevel, 200 X magnification, after 150 passes.

The wear bevel is about 6 pixels wide, the edge is still smooth.

A very good result for a high carbon steel blade, especially given the high bedding angle.

I don't know whether this is just better O1 steel than other O1 steel, or perhaps the cryogenic treatment does make a difference.

150 passes


Check out my jig page for a simple jig you can make in your shop, along with a sharpening set up using sheet abrasives, that reliably produces excellent edges, for all types of irons.

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