How to Sharpen Riding Lawn Mower Blades

Overview

A riding lawn mower blade is essentially a rotary mower blade, much like what is found on regular push mowers. They are made to spin around, fast, beneath the deck of a riding mower, cutting the grass with the whirling action. Over time, the blades will need sharpening. For best results, the blade must be removed from the rider before attempting any sharpening, and all the blades must be sharpened at the same time for mowing symmetry.

Sharpening With a Power Grinder

Step 1

Remove all blades from the riding mower.

Step 2

Secure the blade tightly in the jaws of a vise, with the edge of the blade toward you.

Step 3

Make one grinding pass over the edge with your power grinder. Grind the edge to conform with the factory specifications of between a 30- and 40-degree angle, but this does not have to be exact. Ideally, you'll grind down just enough of the blade to make it sharp. Pits and dings do not have to be ground completely off, as long as the surface around them is sharp.

Step 4

Make one grinding pass at a time, correct the angle and speed with each pass and make another. When the edge is sharpened, move on to the other side of the blade and repeat the process.

Sharpening With a Bench Grinder Grinding Wheel

Step 1

Remove all blades from the riding mower.

Step 2

Adjust your grinder table so that it angles between 30 and 40 degrees. This is the most common angle for blades to be sharpened at, and a bench grinder allows you to make a more precise angle adjustment than a power grinder.

Step 3

Hold the blade tightly in your hands, the edge facing the grinder.

Step 4

Place the blade firmly onto the grinder table and slowly move it across the face of the grinding wheel. Make one pass and inspect the edge. Pits and dings do not have to be ground completely off, as long as the edges around them are sharp. Make as few passes as needed to sharpen the edge, then turn it around and repeat this process on the other side.

Tips and Warnings

  • Safety goggles are an absolute must when doing this kind of work.

Things You'll Need

  • Power grinder or bench grinder
  • Vise

References

  • Grounds Maintenance: How To Sharpen Rotary Mower Blades
  • Lawn Mower Expert: How to Sharpen Your Lawn Mower Blade
Keywords: riding lawn mower blade, secure the blade, a sharp edge, sharpened, grinding wheel

About this Author

Dale Y the Maintenance Guy, has been involved with do-it-yourself projects, household and auto maintenance, property management and worked as a consultant with home and industries, while running a successful home repair business for more than 25 years. His written work has appeared in the "Lacrosse Tribune," "Women's Day," "New Home Journal," and on many DIY websites across the Internet.