Keeping your lawn mower blades sharp and balanced can make a huge difference in how well your mower performs. Dull and unbalanced blades can result in ragged, uneven cutting (resulting in a less aesthetically pleasing lawn) and more frequent grass cutting clogs. Depending on the type of surface area your mower is traveling, proper blade and lawn mower maintenance only needs to be done once or twice per season. And while you can trust your mower in the hands of a capable professional to perform the job, spending an hour or two changing and balancing the blades yourself can lead to significant savings over paying someone else to do it.
Gather the Necessary Tools
Before you begin, make sure you have the necessary tools on hand. These typically include a socket wrench; a blade removal tool (if provided with your mower); a flat blade screwdriver; a sturdy block of wood or a wooden dowel; and, most importantly, a new set of replacement mower blades compatible with your specific model. Having these tools ready will make the process smoother and more efficient. You may also want to have on hand some Loctite and anti-seize compound for the bolt threads.
Practice Safety First
Safety is paramount when working with any power equipment, including lawn mowers. Always ensure that the mower is unplugged, the engine is turned off and that the spark plug wire is disconnected to prevent accidental starts. Wearing gloves and protective eyewear is also recommended. Exercise extra lawn mower care when handling sharp blades to avoid any injuries. Safety should be the top priority throughout the blade-changing process, from start to finish.
Remove the Lawn Mower Blades
Lift the mower deck to expose the underside of the mower. To prevent the blade from rotating, insert a wooden dowel or a sturdy block of wood through the mower’s discharge chute and position it against the blade. This will keep the blade from turning while you loosen the blade nut. Next, use the socket wrench to remove the bolts, being careful not to lose any washers, spacers or pulleys. You may need to use the screwdriver to help break the bolts loose if they are too tight.
Once the nut is removed, slide the old blade off the spindle, being cautious not to damage the spindle or yourself. Be mindful of handling the old blades — even dull blades can be extremely sharp and cause serious cuts.
Inspect and Clean
The old blades are off and you’re halfway there. But before installing the new set, take a moment to inspect the spindle for any signs of damage or excessive wear that could indicate issues. If you notice any, it’s best to address them before proceeding, since they could compromise mower performance. Clean the spindle and the area around it to remove any debris or grass clippings that may have accumulated. This will ensure a secure and efficient blade installation, enhancing the overall performance of your lawn mower.
If necessary, install a small amount of Loctite on the threads for corrosion resistance and apply a small amount of anti-seize compound on the bolt threads to help with future removal.
Install the New Blades
Carefully orient the replacement blades the same as the old ones and place them onto the spindle shaft, ensuring that the cutting edges are facing the correct direction. Reinstall the washers and spacers if applicable, followed by the blade bolts. Loosely attach all the bolts and then torque them down using your socket wrench, following the pattern shown in your operator’s manual. The torque specs are also listed in your manual and should generally be between 65 and 85 foot-pounds. (Take care not to overtighten, as this can damage the blade or spindle.) Finally, remove the wooden dowel or block of wood from the discharge chute.
Balance the Blades
Once the new blades are installed, test the blade rotation to ensure everything spins freely and smoothly. Listen for any unusual noises that may indicate a rubbing or unbalanced blade. An unbalanced blade will cause vibrations that can damage your deck and lead to drive issues.
Now it’s time to test the new blades. Place it on a flat, level surface and start the engine. Raise and lower the blade lever to spin the blades and watch how the deck wobbles or moves. If it’s uneven, you’ll need to attach small amounts of weight to the ends of one of the blades using wheel balancing weights until the deck sits level and still while the blades spin. Test spin the blades after each weight adjustment to dial in the proper balance.
Keep Your Mower in Sharp Condition
With sharp, balanced blades installed, wipe down your mower deck to remove remaining debris and grease. Your lawn mower will now be ready to cut grass efficiently and smoothly for the rest of the season. Taking the time to change and balance your lawn mower blades not only saves you money, but gives you valuable knowledge of how your mower works, which you can apply to future repairs and maintenance.
If you’re in the market for a new mower, or just looking for spare parts, DIY kits or replacement blades, shop Minnesota Equipment’s extensive inventory to get your equipment up and running. Need guidance? Contact one of our four locations for help.