Reel mowers are built to be self-sharpening and their simple but ingenious design almost insures a sharp mower–but, only if you do you part.
Reel mowers operate on the scissor principle–two sharp edges passing by each other. However, in this case the sharp edges are not sharpened like a knife blade. Instead they have very distinct edges passing each other at ninety degrees.
This week I received five reel mowers to sharpen. One customer brought a set of three that are towed behind a tractor to cut a ball field. The set had been used only one season and were in really nice shape with the exception of the cutting services. The only reason these needed sharpening is because the blade cutting services had pitting due to rust. If the cutting service of a reel mower is allowed to rust and form pits, then when the blade passes by the base bar the rust is easily knocked off the blade but due to the pit, the cutting edgle no longer meets the bar.
Since there were eight blades per cylinder, and three cylinders, I had 24 blades to work on. Luckily, a course diamond stone allowed me to remove the pitting and gain a nice shiny flat blade on each.
Now it was time to adjust the base blade so the cutting blades would just meet it as the blades rotated. A very fine adjustment of about 1/32 turn was all it took. The mowers were easily cutting paper strips as a test and all was good.
Do not let your reel mower blades rust. Apply some type of rust preventative or make a quick pass over the edges with spray paint.