So here's a question to ponder...

Exactly how does wood dull steel? Steel is much, much, harder than wood. Yet somehow that soft stuff manages to dull a steel edge. Consider a hand plane, planing some nice clean (that is, no included grit) piece of lumber. Sharpen that blade to a surgical edge, plane for a while, and the blade is dull. What is happening here? Is that nice soft wood managing to rub metal atoms off the blade? That seems pretty unlikely -- except that the blade tip does wear away.