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How to sharpen a rotary lawn mower blade
Servicing your lawn mower on a regular basis is important if you want to have trouble free mowing throughout the year. Winter is the best time to get your mower serviced, usually straight after the last mow of the year in November when the lawn mower maintenance shops are quiet, rather than waiting for the spring when you are likely to be put to the back of the queue whilst becoming frustrated because your lawn is growing so fast the grass biting your ankles.
We carry out our lawn care services on thousands of lawns and our technicians will tell you that the single most important thing you can do during the mowing season is to make sure the blade on your mower is sharp. A blunt blade will tear at the grass resulting in yellow torn tips and an invitation for disease to attack the plant, plus the grass will become stunted, pushed flat and generally unattractive.
Most people in the UK use a rotary mower so here are our top tips on how to sharpen a rotary mower blade. We recommend this is done at least twice during the season to ensure your lawn is getting a nice clean cut.
- Before you come to remove the blades of a rotary mower for sharpening, make sure you disconnect the spark plug of a motor mower or disconnect the lead/battery of an electric mower to prevent any outside chance of the engine being started accidentally. It’s better to be safe than sorry. Having uncoupled the spark plug lead, locate the fuel filler and tip the machine onto its opposite side (ie with the fuel filler and carburettor uppermost). This will ensure that any accidental spillages will fall away from you.
- Check for the sharpness of the blades, if the blade is blunt or has imperfections from stones it will need sharpening. If the blade is badly worn or damaged it needs replacement. We recommend keeping a spare blade to hand so you can always swap them over quickly.
- You can sharpen the blades yourself, using either an angle grinder, or a bench grinder. Always grind at the blade’s original angle, you should be able to feel and see this as you work. Be sure to wear protective hand, eye, and ear equipment.
- Balancing the blades is important, as any imbalance will cause vibration and affect the cut. On a rotary machine, this is surprisingly simple, see all of these steps in the video above.
Sharpening a Cylinder mower blade
Sharpening and balancing of blades for a cylinder mower is more involved and should be done by a garden machinery service shop who has the correct equipment. Cylinder mowers have two blades, the Cylinder and the bottom blade which work together to create a beautiful fine cut. Regular adjustment is required to ensure the bottom blade is aligned perfectly to the cylinder so that the grass is cut cleanly and does not tear, if the bottom blade or cylinder becomes worn or blemished it is time for a re-grind so that the mower can work efficiently.
Cutting height:
For the early cuts in the new season, we recommend you adjust the cut to its highest setting. In any event, it is always vital to ensure you never cut away more than half of the grass’ height in one cut as this sends the plants into shock and retards its healthy growth enormously.
Not only is your lawn mower an investment for you, but it is also vital to keeping your lawn healthy. So, if your first cut of the season is delayed because the mower is out of action, your lawn may well suffer as a result. Be kind to your mower, and you will be kind to your lawn too.
If you do not have the time to service your mower, or would prefer not to do it yourself, just make sure you do not leave it to the last minute and have to join that giant queue!