How To Sharpen Lawn Mower Blades – Your Ultimate Guide

Lawn mowers are undeniably a hugely important tool for the gardener. Whether you’re a casual spot of gardening type person, or a full blown green fingered fanatic, the lawn mower is a pretty essential part of the gardening routine!

Keeping your lawn mower blades sharp is so important! Often people don’t even look at how blunt their blades are, but you really run the risk of yanking your lawn instead of a nice clean slice, which is not only nicer but healthier for your lawn as well. A sharp blade keeps your mower running in tip top condition and will mean less effort for you in the long run. I’m going to give you a few of my favourite tips on keeping your blade extra sharp, and all from the comfort of your own garden.

A lot of people probably are wondering whether you can safely sharpen the blade on your own lawnmower. The answer is “YES!” And you’re probably now wondering how to do it? Well keep on reading and you will find out how.


Firstly you must make sure the mower is not attached to the mains! It might sound obvious, but better safe than sorry!

So, very simply, remove the blade by unscrewing the nut that attaches it to the motor. Remove any ruse with a steel brush or steel wool. This is easy to acquire at any hardware or gardening store. Give it a good old brush with some elbow grease, till the orangey colour has gone.

Then you’re going to need to get hold of a clamp or a vice. Most DIYers will have one of these in a shed, but if not, don’t be afraid to pop over and ask a friendly neighbour! Clamp the blade in a vice, or to the edge of a solid work surface. Now were going to file the blade. Run the file along the cutting edge, thats the narrower sharper edge, trying to follow the same angle on the blade.

In some cases the blade can be badly damaged. This could be from long-term use, or from trying to cut through tougher things than your mower can handle, or from kicking up rocks or wood getting jammed. If it is badly damaged you may need to use a bench-grinder or have it professionally sharpened, which shouldn’t be too expensive if you shop around. (again just pop down to your local hardware store and ask around there)

If you do use a power grinder sharpen your blade, make sure the blade doesn’t over heat. This can weaken the blade, so be sure to dip the blade in water frequently during the sharpening process.

To remove any nicks or grooves you need to run the blade along the grinding wheel. Then hold the blade at the proper angle (the angle already on the blade) and grind the length of the blade until its sharp.

Remember, you want your blade to be about as sharp as a butter knife, it shouldn’t be as sharp as a razor blade. Not only do you risk cutting yourself, but the blade will curl in places where it hits little pebbles or wood. There is no need for it to be this sharp as the speed and angle will cut the grass perfectly at this sharpness.

There is a “lazy” way of sharpening your blade which would be to use coarse grit sandpaper. If you don’t have large nicks in your blades this will do the trick as a quick fix, and will clean up the edge nicely.

To check that the blade is balanced you simply need to balance the blade from the counterpoint on a Blade Balancer, a very inexpensive tool, or a nail. If the blade isn’t balanced, you can remove some of the material from the heavier side, but make sure not to remove it from the cutting edge.

Now that your blade is all nice a sharp, you can re-attach it to your lawn mower with the nut.

The more you sharpen your blade, the quicker and easier the task will be. If you frequently use your mower, I would recommend sharpening your blade every couple of months, but you can be the best judge of that. If you notice that your mower isn’t cutting as finely, maybe its time for a sharpening!

A few points to remember! –

  • Butter knife, not razor blade
  • Don’t change the over-all angle of the blade! (the manufacturer probably knows best!)
  • Make sure you’re balanced, this can harm the mower permanently
  • Curved mulching blades might be harder to sharpen, you could think about simply replacing it
  • Replacement blades can be found quickly and easily, don’t be afraid to just replace it!

So, now that you know how to sharpen your lawn mower blades, you can easily do it yourself! No more chopping and hacking at that lawn with a blunt blade, the 15 minutes it took for you to do that has surely taken a lot of the stress and sweat out of your lawn mowing!

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