What I Learned Today

I have a lawn mower (reel mower) that is purely mechanical: you push it and as it moves it spins five curved blades that chop up the grass. It has no engine and uses no gas or electricity. Mowing the lawn with it is a nice exercise: you push it along and it makes a quiet snick-snick-snick sound as it cuts the grass. I’m very fond of it!

Yet over the years the blades grow dull. I figured I’d need to take it to a sharpening service, but then I found this Instructable that shows you how to sharpen a reel mower yourself. It’s quite clever *and* easy to do! You use the mower to “lap” its own curved blades, meaning to sharpen and align them by running them backwards against the fixed blade (“bed knife”). As advertised, this was straightforward: I swapped the gears on the two wheels, adjusted the bed knife (this was actually the trickiest part for me), smeared on “grinding compound” (I ordered this Permatex compound for just $4!), and then pushed the mower around for a while with its blades grinding each other smooth/sharp. In this process I also got to study just how the mower works (I love decoding machines) and to admire the built-in ingenuity and simplicity of it.

At least, that’s what it was supposed to do. After I’d pushed it for a while, I felt the blades with my finger. They had turned shiny (see picture at right), but didn’t feel sharp. I decided to give it a try. I swapped the gears back, readjusted the bed knife, and took my mower out to the lawn. And whoa! It cut the grass WAY BETTER than it had for a long time. In fact it cut it much shorter than before – I think with dull blades it was bending the grass over and cutting it longer. I had *wondered* why I had to leave the mower on the lowest height to get anything reasonable. Now I can set it to a higher (correct) setting and get the desired grass height. Very satisfying!