> hitting with a (relatively) blunt object in the first place

Well there's your problem right there.

Lawn mower blades are meant to be somewhat blunt. Like a butter knife. Too sharp and the blade will chip away on the harder materials.

	▲	SoftTalker an hour ago \| parent \| next [-]
		I have a battery electric lawnmower. I found I got noticably better battery life after sharpening the blade to a near razor edge. Yes the edge is more fragile but it cuts the grass with much less resistance.
	▲	sunrunner an hour ago \| parent \| prev [-]
		That I did not know. I still wouldn't stick a finger near one of course.