updated 18 May 2008

This site presents results of tests that compare the properties of different types of steel used to make blades for woodworking planes.      

I’m attempting to answer these questions:

• With equally fine honing, do some blades reach a higher level of sharpness than others?
• Which honing abrasives work best on each type of steel?
• How well do the blades hold an edge when used to plane different species of wood?
• What bevel angles give the best performance?

I’ve tested a number of blades from commercial manufacturers and blades I made myself from a particle metallurgy alloy called CPM 3V.

I have a related site called Tuning & Testing Infill Planes that describes my efforts to learn how to bring an infill plane to a high level of performance.

Topics explored include:

• Chipbreaker Design
• Mouth Dimension
• Types of Shaving Formation

Methods of Testing

I use this toy microscope to examine the blade edges before and after use:

The quality of a freshly honed edge can be evaluated to ensure that remnants of wire edge have been removed and that no defects are present. After the blade has planed a measured amount of the test species it is examined again to check for chipping, deformation, and wear. Here is an image of a freshly sharpened blade edge:

This is the same edge after making 400 lineal feet of shavings:

Each image magnifies a portion of the blade that is slightly over 1/32” wide. Images of common objects at this scale can be seen here. In the images above, the scratched area in the lower left corner is from the grinder, the lighter band above it is from 3 micron diamond paste, and the darker band is from 1/4 micron diamond paste. In the lower image wear is visible as a lighter area along the edge.

In addition to making microscope images, I test the sharpness of the blades by measuring the amount of force it takes for the blade to cut through a loop of thread. By performing repeated tests it’s possible to get a numerical value for the sharpness of the blade. Further information about this test can be found here.

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