Stay Sharp! How to Sharpen your Mower Blades

Grass Tips

Nothing will improve the performance of your DR Field and Brush Mower or lawn mower better than a freshly sharpened blade.  When you sharpen your mower blades, grass, brush, weeds, and saplings are cut more cleanly and require less power from your engine.  On a lawn mower, grass is cut more cleanly and you reduce your risk of grass disease caused by a dull blade.  You’ll know if your blade is dull if the tips of your grass are white and ragged looking, instead of clean and green.

You can have your blades sharpened at almost any lawn mower service shop.  They usually charge less if you remove the blade yourself, and a bit more if you bring them the whole machine.  Over the life of your mower, though, it pays to sharpen them yourself.

Remove The Blade


The reason mower shops charge more to remove the blades from your machine is that the rust, dirt, and grass build-up can sometimes make it very difficult to loosen them.  Before you try to remove the blade, disconnect the spark plug and make sure the plug wire can’t slip back into contact with the plug.  Next, either place the machine on a workbench or prop up the deck with a Mower Jack.  Looking at the underside of the deck, the nut holding the blade unscrews in a clockwise direction (this is a reverse thread).  This nut is likely to be corroded and very tight, so first apply some penetrating oil to the nut and the blade shaft and let it soak in.  Holding the blade shaft above the deck (just under the pulley) with a 1″ wrench, use a 1-1/4″ wrench or pipe wrench on the nut holding the blade.  To apply leverage, slip a 12″-14″ piece of pipe over the wrench handle and turn clockwise.


Sharpen The Blade

Wear good quality gloves when handling the blade to avoid cutting yourself.  Place the blade securely in a vise.  You can use a coarse mill file (good) or a diamond file (better) to sharpen the blade.  File the edge of the blade in a long, sweeping motion in one direction at the same angle as the edge that is already there.  On the DR Field and Brush Mower, this is about 35 degrees.  You will need to remove enough material along the entire edge so that any nicks or gouges are removed.  Do the same to the other side.

Balance The Blade


Because you are removing metal from both sides of the blade, you need to make sure you remove an equal amount from each side in order to keep the blade balanced.  A badly out-of-balance blade will cause your machine to vibrate excessively.  In addition to being uncomfortable to operate, it could eventually damage the blade shaft bearings.  The best way to balance the blade is to purchase a blade balancer at your local hardware or auto parts store (they are usually under $5).  After sharpening the blade, place it on the blade balancer and check the level.  If one side of the blade tips lower, you need to sharpen that side more to balance the blade.

After replacing the blade, you’re all set for clean, efficient mowing.  You can save a lot of time and energy by having a spare blade on hand.  That way, you can always have a sharp blade for mowing, and can sharpen the dull blade when you have time.  If you have a DR Field and Brush Mower, consider keeping additional brush blades on hand for when your blade starts to dull. Happy mowing!

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