You could have dulled the blade. If you can safely tip the mower in the proper direction (air filter facing up ) and have a look at the edge- that should tell you a lot. They are not razor sharp, usually around .020" if you can compare it to a couple of business cards stacked maybe.

Butter knife sharp is the rule I use when sharpening blades.

I like razor sharp, and you shouldn't use a lawn mower in the dirt or to 'scalp' on purpose.

The argument will be 'you shouldn't make them sharp because they will get dull faster'. That's true, but after they lose the razor edge they'll be down to where you start with your 'business card' edge, and I will have enjoyed a few cuttings with that unmistakeable 'sigh' of a really sharp blade cutting grass. After that, it won't dull any faster than yours, so technically I have increased the interval between sharpenings by a few days.

I have sense enough not to cut myself on a sharp mower blade and would sincerely hope anyone on the forum would too. I clean a used blade and inspect, then chuck it up in the vise and sharpen each end with various files. Sometimes if helping someone else out I'll be forced to use the bench grinder because they have hit so many hard objects. In either case, I check static balance and adjust if needed. Then I paint the blade with whatever kind of black I might have around and put it back into the rotation.

When I check the blade before sharpening, if I find the airfoils are thinner than 1/16", or any other serious problem, the blade is done and is trashed.

Ditto Saxman,s response !

You might try purchasing a GATOR blade that would give a more manicured cut and mulch the grass significantly better that a standard straight blade.

Makes sense to me Ted !