The blades are one of the most important parts of a lawn mower – if not the most important. If the blades are dull, cutting grass will be a difficult and frustrating experience. The blades may seem small size, but there is more to the blade that meets the eye… or the grass.
Blade Maintenance: When to Change Lawn Mower Blade
When it comes to using lawn mowers, it is important to know when to change lawn mower blade. A dull blade does not cut the grass; instead, it either bruises or crushes the grass.
That being said, the yard becomes exposed to the damaging effect of the sun and some grass diseases. So when the blade starts to become dull, it is the right time when to change lawn mower blade.
Before changing the blade, make sure to remove the spark plug in order to make sure that the machine does not accidentally turn on while removing the blade to avoid any accidents.
Keep the blade stationary using a blade buster, a vice grip or a simple blockage, and use a wrench to remove the nut that keeps the blade attached to the engine with your other hand. After retrieving the blade, inspect it in a vise.
If the blade contains some nicks, it can be filed away using a file (preferably flat medium) or a Dremel tool. Do not remove too much metal while filing the blade because an unbalanced blade brought about by too much filing can cause uneven cuts.
To check for the balance of the blade, place it on the handle of a screwdriver. If an end points up, sharpen the other until balance can be achieved. Scrape off accumulated debris from the blade returning it to the lawn mower. Return the spark plug after.
Sharpening the Blades
Aside from knowing when to change lawn mower blade, it is also important to learn how to sharpen the blade. Sharpening the blade is an easy thing to do and does not necessarily require the expertise of a lawn mower mechanic. Sharpening the blade can either be done by hand or with the help of a machine. To go about with both methods, here are simple instructions to follow:
- By hand – Clamp the lawn mower blade with the help of a sturdy clamp or a bench vise and put it on a comfortable working condition. If one wants to work while sitting, the vise or the clamp can be placed somewhere at the level of the waist. Make sure to put some old newspaper beneath the work place to make clean-up easier afterward. Find a metal file to sharpen the blade. Start from the inner edge to the outer edge and repeat the process until a shiny, clean edge is achieved.
- Flip the lawn mower blade over so that the same process can be done on the other edge of the blade. Just follow the angle of the factory bevel while sharpening the blade. If in doubt, check the user manual for confirmation. The blade of the lawn mower does not need to be super sharp like a knife because it still it can simply rotate at a high speed in order to cut grass.
- By machine – Safety is the most important thing in doing this process. Use eye protection, gloves, and long sleeves to protect the skin from projectiles and sparks. In going about this process, a bench grinder is essential. Just move the blade back and forth and make sure that the bevel of the blade is maintained as it is being sharpened. In the absence of a bench grinder, a hand grinder – at least 4 ¼ inch – can be used with a metal wheel. This method can accommodate the alternate use of a belt sander together with the grinder.
- Invert the belt sander so that it faces up and then lock the trigger to the “on” position. The blade can get really hot after so it is important to quench the blade so that overheating can be prevented. Overheating should be avoided because it could lead to the blade’s weakening or warping. Do the quenching using a bucket of water frequently. When the blade starts to become hot, dip it into the bucket and then dry the blade first before repeating the process of sharpening the blade. After the blade has been sharpened completely, return the blade to the lawn mower.