Lawn Mower Blade Sharpening Techniques, Tips & Tools
Updated: Dec 28, 2018
Here are some great ideas and hints to help you sharpen your lawn mower blades the easy way. In this article I feature a few fantastic tools to help make sharpening blades much easier.
One of the initial challenges that you will likely encounter when you attempt to remove your mower blades after of full season of operation is the difficulty of loosening the retaining nuts that hold the blades safely in place. These fasteners are usually very tightly secures and take significant force to loosen. You can achieve the necessary leverage to loosen the nuts by using a breaker bar or torque wrench, however that second issue that you are likely to encounter is that it is likely to be extremely difficult to keep the blades stationary so that you can exert the necessary force needed to loosen the nut.
In order to secure the blades to keep them stationary it is necessary to safely block the movement of blades. This can be easily done by securing a piece of wood on the inside of the deck. The block of wood should be large enough to catch and stop the movement of the blade. The wood should be secured by a large c-clamp and you should also use a smaller, protective block of wood on the exterior side of your mower deck to prevent damaging of the painted surface.
When securing the wood to your deck keep in mind the old adage "righty tighty, lefty loosey", In other words, you will need to turn the nut to the left, (counterclockwise), in order to loosen the nut. Conversely, you will turn clockwise or to the right when you want to replace and tighten the blades. With the blade secured from movement and with the correctly sized socket and proper leverage, you are now ready to remove the fasteners to release the blades.
Although I have not tried this tool, there is also a device listed on Amazon that attaches to your mower and is described as capable of holding a blade in place for faster, safer removal. it is recommended for walk-behind and riding lawn mowers, either single or twin blade models. It is touted by one reviewer as "the most practical and useful thing I've bought to help with my mower." I'll leave a product link below.
With the fasteners off, you want to note the position of the blades before removing them from the deck. It is recommended that you mark the down side of the blade as an indicator of the correct side to mount the blade after sharpening. Otherwise you chance mounting the blades upside down.
Before sharpening the blades you should visually inspect the blades for fitness of operation. If the blades are bent, are worn or thin, have cracks in them or have chunks of metal missing, then they should be discarded and replaced with new blades. Assuming the blades are is good condition, you should prepare for sharpening by donning some personal protective equipment, (PPE).
Proper PPE includes having a sturdy pair of work gloves and protective eyewear. The work gloves protect your hands from possible cuts or burns from metal sparks that may be produced by grinding of the blades. The protective eyewear will shield your eyes from the molten sparks. With your protective gear in place you are now ready to put a nice sharp edge on those blades.
Blade sharpening can be made easier and much safer with the proper tools. I know many how recommend a hand or bench grinder for sharpening, however these tools can be dangerous to operate by the inexperienced user. On a bench grinder the mower blade can be accidentally lodged between the grinding wheel and the tool rest. If this happens the grinding wheel could explode causing wheel fragments to be hurled at you at unimaginable force and speed. The same is true of the disk on a handheld grinder if improper angle and force is placed on the grinding disk.
A safer solution is a grinding stone drill attachment specifically made for sharpening blades. The blade sharpener that I use and recommend in the Arnold Lawn Mower Blade Sharpener which can be found on Amazon. This fantastic tool fits any 1/4" or 5/8" electric drill, gives you a sharp edge in minutes to ensure clean cut for a healthy lawn.
I also recommend that your use a good blade balancer to ensure proper balancing of your blades. Blade balancing is essential for smooth mower operation. More importantly, properly balanced blade will eliminate blade vibration. A vibrating, unbalanced blade can result in premature wear and possible damage to your mower's engine or deck blade spindles.
You should begin sharpening once your blade is secured in a proper bench vice. The vice should be capable of holding your blade securely while you use your drill mounted blade sharpening wheel to grind the cutting tip of the mower blade to perfection.
Using the Arnold Blade Sharpener, you should place the grinding wheel on the edge of the blade with the plastic disk of the flat side of the blade. Be sure to keep the wheel horizontal and perpendicular to the blade. Just take your time and move the grinding wheel up and down the blade wheel with smooth movement and light even pressure.
After grinding both sides of the blade to sharpness, test the blade for balance. If the blade does not rest on a level horizontal plane, you will need to remove additional material from the side of the blade that rest lower on the blade balancer. One you achieve a good edge and the blade is balanced you are ready to mount and start mowing.
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