My WordPress is long overdue for updates, so I’m just going to do a bunch at the same time while I have a little break from schoolwork.
This post won’t necessarily be helpful as a how-to post, and more of a this-is-possible post, because it’s way easier to learn this from a video or from someone else than it is to learn from pictures and text, but here goes.
I started a little company (really just some online postings) for a sharpening service while I’m in Pittsburgh, because for some weird reason, I couldn’t really find anyone in the area who offered knife sharpening. Anyways, I got a call from someone asking if I could sharpen a push mower, so after watching some videos and reading an Instructable, I figured out how. Before I dive into steps, if you want to follow along, you’ll need the following tools:
- Flathead screwdriver (popping off e-clips and adjusting blade)
- Valve grinding compound
- Cordless drill (makes things a little easier)
So the first thing to do is to pop off the wheel cap, e-clips (retainer rings), and wheel. This way, I could rotate the blades without the wheels spinning around.
After that, I popped off the little gear. Inside it, I could see how the ratcheting mechanism worked. There’s a little almost trapezoidal shaped metal bar that sits in a slot in the shaft of the blade assembly. Pushing the mower will engage the wheels with the blade assembly, spinning the blades, while pulling the mower will disengage the two parts, so the blades stop spinning.
There are two screws on each side of the mower that adjust how close the stationary blade is to the spinning blades. For sharpening, I adjusted them a little closer together such that the spinning blade assembly could still rotate but with quite a lot of force. The blades will be used to grind each other to sharpen everything up.
I loaded all the edges with the valve grinding compound, which is basically just a bunch of sand in some sort of past-like suspension. The abrasive will allow metal grinding that sharpens the blade edges.
One of the videos suggested using a cordless drill to rotate the blade assembly. Unfortunately, my cordless drill chuck didn’t fit over the axle. The Instructable suggested flipping the ratchet assemblies (left to right and vice versa) to “run” the mower backwards, so that’s what I ended up doing instead. Important note… spin the blade assembly backwards and not forwards, otherwise you’ll be dulling the blades instead of sharpening them.
After running the blades backwards for some time and cleaning off the valve grinding compound, I could see that metal had been removed from the leading edges of each of the blades.
After cleaning off all the grinding compound, I adjusted the blade distance again such that the blade edges were touching along the entire length but not too difficult to turn. To make sure everything was nice and sharp again, I grabbed some paper, stuck in between the blades, and checked the sharpness for each of the blade along the entire length of the mower.
The last step was to clean out the old grease from the gear and ratchet assembly, pack with new grease, and reassembly everything (making sure the mower blades spin in the correct direction).
Hope that was useful to someone. Again, there are plenty of Youtube videos, and they’re probably much more helpful for learning how to do this.