what exactly did you mean by not being impressed? poor cuts can be a result of several factors.
uneven cutting is often due to deck not being level, tires not having equal air pressure or a bent blade.
if you look at the cut grass closely, the tips should have a cut look as opposed to a ripped look. cut look = good sharp blade. ripped look = dull blade, insufficient blade tip speed and will give you lawn a dull, brown appearance due to tip rot.
if you see a space of uncut or bent over grass in between the blade tracks, they are too worn or have been shapened incorrectly. the tip of the blades should not have material removed past the point where the blade starts to bend up towards the trailing edge. think of it as a propeller or fan blade. where the blade starts to curve up directing air flow upwards to give "lift" or suction to the deck, the shapened edge should not impinge on that area of the blade. once it does, the blade is worn out and should be pitched on the scrap iron pile for other projects.
furthermore, the cutting surface of the blade should not be curved like a paring knife, but be as straight as possible like a santoku knife. this is virtually impossible to achieve as the blade gets older, especially if you have any rocks, since large dings usually appear near the tips and material there gets removed for deeply when sharpening.
blades should be sharpened on one side only. the flat side should remain flat, and only the angled side should have material removed from it and the angle should remain as constant as possible. this is very difficult to do with a bench grinder unless you have a proper blade jig. it is virtually impossible to do with a grinder on a mulch or 3 in 1 blade. you need a good fixture to maintain the proper angles.
all of these are reasons why no blade will ever cut as good when new or after the very first sharpening.
hope that helps!
amp
