Hand Tools

Subject:
Re: Normal Day to Day Testing
Response To:
Normal Day to Day Testing ()

Derek Cohen (in Perth, Australia)
I stroke tested the two irons. I don't have the document, but found the LN iron to last longer because it chipped less. On a piece of maple about 20 inches long, I ended the session of 2 thousandth shavings (advancing the iron as I was working if the shavings did not continue to measure 2 thousandths) with 770 or something with the IBC and around 1100 with the LN, Perhaps it was 1050. I remember that it was 4 digits. Would the result have been different after an eighth of each iron was used? Possibly, I don't know.

At any rate, that is what I would consider to be a practical test. There's no cocobolo with visible silica particles in it that look like tiny diamonds, no MDF and no planing across the end grain of something janka 2700. 99% of the stuff I plane is somewhere between softer cherry (low quality) and hard maple.

It took quite a long time to plane the 1800 or so strokes that i planed with an LN smoother and those two irons, and it was careful work to try to perform all of the strokes identically.

Before we conclude that V11 lasts to the moon, I would like to see a test like that. In "normal" wood that most people plane. Not across endgrain, not MDF.

David, that is YOUR idea of testing. You and Brent can stroke away 2000 shavings per blade. Good luck to you! :) I do not have the patience for that, and believe that there are more efficient ways to test an edge.

Lee Valley's idea of planing MDF is very reasonable. It offers an abrasive surface (quicker wear = quicker testing) that is reliable, reproducible, and fairly universal. It's not Real Wood, and this bothers you.

The fact is that one is unlikely to find a real wood board that another will be able to plane that is identical for all. The best one can do is set parameters that others can understand and infer from.

What did I do? I chose a wood that I knew to be abrasive and used the same piece for all blades. I used a shooting board (Stanley #52) as this controlled the action of the blade on the wood. I used the same plane (LN #51) for each blade. I sharpened the blades at the same angle (30 degrees). All that differed was the blades: Clifton O1 (about 10 years old); Smoothcut (about 10 years old), and PM-V11 (about 2 months old). If anything, the PM-V11 was at a disadvantage with respect to chipping, as it was the newest. The other two blades had long been worked past the brittle area.

All blades could pare end grain pine to start. The question was, at what point would they stop doing so after planing the hardwood end grain? That is a measure of real world sharpness and edge holding. I am not looking at a test of ultimates. That would have less to offer the woodworker, who really wants an estimate of a blades longevity. The paring of end grain also aids in ruling out a blade as "working" sharp if it is cutting with chips.

This way I could conclude that the PM-V11 was able to do 60 shavings without affecting the paring of end grain; the Smoothcut was tired by 40 shavings, and the Clifton gave up the ghost at 22 shavings.

That tells me a lot.

Regards from Perth

Derek

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