Hand Tools

answer *PIC*

Bill Tindall, E.Tn.
The picture is made after the blade was used to plane some feet of wood. The tiny bumps may be iron carbide crystals embedded in the iron matrix. It appears that the iron, which is softer, has worn away from these regions, consistent with the fact that iron carbide is way harder than bulk iron metal.

I saw something similar in an earlier study of whether a coating of Titanium Nitride (yellow) on an A2 blade would prolong edge life (it didn't under the conditions explored). The picture is after this blade planed 50m of hard maple. The titanium nitride has worn from the edge leaving a bumpy surface similar to David's picture.

The picture was made with a Nikon metallurgical microscope. The scale is accurate. It is remarkable that David is getting pictures nearly this good with a scope 1/100 the price.

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