How to sharpen a reel mower blade

Grinding the cylinder of the lawn mower is very important to get the best outcome to every lawn mowing job so well show you how to sharpen reel mower blade or cylinder mower blades.

Usually, when you grind the cylinder it is a must to grind the knife blade as well.

The most common way to sharpen the cylinder is by using a grinding compound and spin the cylinder either by hand or motor, but this can only be applicable to small and thin cylinders like the push behind lawn mower that we use in the old days, the one that uses the wheels to drive the cylinder, but it is still available in the market today.

A course grade of grinding compound is used for starting, you apply this compound to the blades of the cylinder, then you adjust the knife blade so it touches more and start spinning the cylinder in this way the cylinder is being sharpened, and if you want to get a smoother finish you can apply a fine grade compound for the final pass.

Reversing the Reel or Cylinder

A Reel or Cylinder can be reverse depending on how bad bad the blade is , if the reverse side of the blade is still sharp then its find to reverse the cylinder.

But keep in mind that not all cylinder type lawn mowers can be reverse it depends on the brand or the construction of the cylinder, if both ends of the cylinder is the same then it can be reversed for example if the drive side is female and the opposite is also female then its fine to reverse the blade,

Cylinder Grinding Method the Professional way

A much better and more professional way of grinding a cylinder is being done using a grinding machine so most of the time this job can only be done on a shop which will require you to spend some extra bucks but I can assure you that you’ll be 100 percent satisfied on the outcome on this grinding process.

This grinding method is essential for thick and long blades which is mostly use by contractors so spending a few bucks for professional sharpening is not an issue for them.

If your skilled enough to build your own grinding machine well that’s awesome you can grind your own blade or you can make money by accepting grinding jobs.

Just a few tips before attempting to grind a cylinder, First make sure you check the bearings of the cylinder if you notice that its running dry then you must replace the bearings or if its physical damage and had a huge side play.

Also a Reel or Cylinder must always be grind at bearing surface which means a bearing must be inserted to the journal and must be hold by a housing that’s being held on the grinding bed.

Grinding speed is also a factor in getting a smooth and shiny finish on the blade, the faster you making a pass on the blades the rough the finish is, so just grind slowly in this way you the grinding stone can last long.

As you can see on the picture its a 28″ cylinder being a grind, you’ll notice the shiny appearance of the blade when your grinding at slow speed, especially on the last pass.

Every time you finish a complete pass you can physically check the blade if it’s totally sharp or it needs more.

How to Replace a Bottom Blade of a Cylinder Mower

A reel or cylinder lawnmower is always composed of the blades the reel or cylinder and the bottom blade or the knife blade.

The length of the knife blade is always equal to the length of the cylinder which ranges from 17″ to 36″ depending on what brand.

From the most common mechanical push behind lawn mower that’s been driven by the wheel motion to the big ride on one’s they all have these pair of blades.

Sharpen or Replace Blade

The truth is you don’t need to replace the knife blade frequently, If the lip of the blade is not badly or completely worn out it can still be grind.


A blade is still good to be grind if it still have a thick edges at the front where the cylinder touches,

If the front edge is already pointed there is no other option but to replace the blade

Procedures in Replacing the Bottom Blade

Replacing the blade starts by removing the blade from the sole plate by removing the screws that hold the blade to the sole plate.

Mostly the head of these screws are tapered and can only be driving in and out using a rattle gun with a flat or plus screw bit, during the screw removing process some of the screws might become too hard to remove especially when the blade is never been served for a long time. so you will need a pin punch or punchers to drive the screws out.

Once the old blade is remove don’t forget to clean the sole plate, the flat area where the new blade will seat, Use a sandpaper and CRC or rust remover to clean these part, If the thread for the screws has been unintentionally stripped you must need to run a tap on that thread so that it will easy to put the new screws.

When the sole plate is ready you can now put the blade in place but before putting the blade, coat with grease that flat surface where the blade will seat.

Next, one by one you can start to put the new screws on top of the blade and tighten them with the rattle gun.

Cylinder Mower Bottom Blade/Knife Blade

It doesn’t mean you don’t grind the blade if its new, The blade needs to be perfectly flat and square so you need to give a run on the grinder to make sure that it will cut equally and uniform otherwise you will leave a line in your lawn.

The knife blade needs to be grind on two sides the top part and the front part, When grinding the top part you need to grind on an angle touching the rear of the blade to the stone first so that when the reel or cylinder blade spins it will only strike on the knife blade edge creating a scissor like action that cuts everything in its way.

Also take care not to get the knife blade hot while grinding, when it gets hot it will hot get you a good finish, when the blade metal gets hot it will bend on the hot portion and will give you a sharp but a not cutting spot.

It’s recommended to have a running water or coolant that cools the blade while grinding to avoid the blade from getting hot.

The procedures of grinding the new blade also applies to a blade that is still good and can be sharpen.

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