"Pete S" fired this volley in
:

I think you would waste a lot of blade material by milling. The
problem that I have is that the tips of the blades wear away faster
than the rest of the cutting surface.

That's why the acceptable profile may include an angle from inside to
tip.

Yes, you remove more metal by milling than by "selective" grinding, but
there are advantages.

One: once it's jigged up the first time, it takes only two or three
minutes to mill the ends, and the blades are usually spot-on for balance
after.
Two: A "hollow grind" was suggested here... that's wrong on a mower
blade. When so done, the edge wears faster, and the "shoulder" at the
back of the hollow erodes quickly if there's any sand in your mowing
field.
Three: It's what Oregon recommends for optimum cutting with their blades.

I get roughly 30 acres per sharpening -- that's five mowings of the area
I mow weekly. A blade lasts through about 10-15 sharpenings.

So, I get more than a whole year's worth of mowing from one set of
blades, and a new set of three is about $40. For me, at least, it's
worth it to get that "golf course" look in the front of my property.

I have three "working" sets used in rotation, so I don't have to stop for
sharpening, if I decide they need it. It only takes five minutes to
change a set of blades on the Scagg 61" deck. Except for dropping the
blade bolts out of the spindle bores, it's all done from the top of the
deck, with no removals or loosening of any other components.

LLoyd