Not sure what you did to the blade?? You actually sharpened the curved reel?
I mowed with these for years. First a push model, and then I found one with a tiny 2hp Briggs and Stratton and a jaunty little striped canvas grass catcher basket.
In the old days they had elaborate grinding machines for sharpening the reels. Those were long gone before I started.
So to sharpen mine I used the bed knife and valve grind compound.
One wheel is the drive wheel. It has a ratchet mechanism under the wheel. If you take that off you can reverse the ratchet.
I would reverse the ratchet, set the bed knife pretty tight, load the blade up with compound and then spin the reel backwards. First I made up a crank handle and did it by hand, but eventually a rigged up a small pulley/motor to do it faster.
When the blade was as sharp as I could get it, I'd clean well and set the bed knife for very light drag.
They always cut good for me.
But if you found a method for actually hollow grinding the reel, I would love to hear.
I still have a trimmer/edger.
This is 1/2 a reel with only one wheel, so you can mow against a fence. The edger part is a large round blade you flip the mower upside down to use.
I have hardly ever used it. I got it in almost mint condition.
yours Scott