PM-V11 Spokeshave Blade for Leather

Modified 151 spokeshaves are used by bookbinders and leather workers for reducing large areas of the thickness of leather and are especially good at creating a long gradual bevel. They are also indispensable for working calf, which is difficult to pare using a Scharf-Fix machine. I’ve been experimenting with the somewhat new Lee Valley PM-V11 spokeshave blade. PM-V11 is a proprietary steel designed for woodworkers, and reportedly has the ease of sharpening of 01 steel and the durability of A2.

I’m glad they did some testing of O1, A2 and PM-V111 metals, but have some problems with their methodologies. Most importantly, the assigning of a 0-10 rating for wear based on subjective visual examination, rather than the industry standard CATRA testing machine. Then a deceptive XYZ plotting of wear testing, impact resistance, and ease of sharpening all together creating a three-dimensional triangle. Where is Edwin Tufte when you need him?  They have developed a clever method of quantifying ease of sharpening, however. Oddly, at the bottom of The PM-V11 story page, they negate the need for testing, and lay on some aw-shucks folk wisdom, claiming that woodworkers don’t need an advanced degree in metallurgy or a scanning electron microscope to realize PM-V11 is a better blade.

In any event, I was still curious.  In order to work effectively on leather, first I reground the blade to 20 degrees using a 2 x 72″ belt grinder. Then I hand sharpened an A2 and PM-V11 blade side-by-side. There wasn’t much difference in the time it took. The PM-V11 blade did feel a little gummy, which some woodworkers speculate may be due to vanadium in the blade. Edge retention seemed quite similar, though possibly the PM-V11 lasted a bit longer. PM-V11 did seem to have slightly better initial cutting performance (sharpness), however. Most importantly, PM-V11 was quicker to strop back into action than A2; it felt more like an M3 steel.

Even though PM-V11 and A2 don’t seem to be massively different, I will continue to experiment. Both of these steels are excellent. Yet, concentrating on subtle differences can reinvigorate interest in repetitive handwork, helping to stave off the inevitable boredom which looms at the edges of all professional craft work. Or, put another way, buy more tools.

Information about the history of 151 spokeshaves. At the end of this post there are tips on how to modify and use them for leather work.

Or you can purchase a already modified 151 spokeshave and blade for leather.

leather

Note the thinness of this leather shaving from a 151 spokeshave and PM-V11 blade. Spokeshaving should produce shavings, not dust.

leather2

A display of very regular shaving morphology. A sign of a sharp blade that stays sharp.

 

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