Sharpening rotary mower blades

[Old560]

So what’s the consensus on sharpening rotary mower blades? What point do you replace them? I put the tape measure there just for reference. I went ahead and sharpened these. is the leading edge supposed to have a little bit of a blunt edge not razor sharp to help it last longer? 6 ft. king cutter. Thanks.

 

[m16ty]

I’ve found out that a dull blade seems to cut just as well as a sharp one.
I don’t sharpen unless they get really bad, and by that time they usually almost need replaced.

 

[Ray,IN]

Grind a new edge at an increased angle than the original design. I used my 4" angle grinder to put an edge on new blades this afternoon. The edge lasts longer. The factory stamped "edge" leaves about 1/16" blunt edge.
That said, a blunt edge is best for cutting heavy brush, it shatters the stump instead of a clean sharp cut which can puncture a tire.