Should You Sharpen New Lawn Mower Blades Before Installing?

Imagine this: you purchase a new lawn mower blade, pull it out of the box, run a finger along its edge and think...wait, this doesn't feel very sharp. Aren't mower blades supposed to be sharp, and should you sharpen your new blades before installing them on your mower? For most new lawn mower blades, the answer is generally no. New lawn mower blades are designed to be installed and used straight from the factory, and they already have a functional edge set at a manufacturer's bevel.

Also, keep in mind that lawn mower blades are not supposed to be razor-sharp. Instead, they only need to be as sharp as a butter knife to cut the grass properly, and you should not try to sharpen them like ordinary kitchen knives. It is one of the biggest mistakes people make when sharpening lawn mower blades and it can result in damage to the blades and to the mower itself. Also, keep in mind that lawn mower blades sometimes have a protective coating on their edge that can make the blade edge feel dull. This coating is there to protect the blade when it is stored and shipped, and it will naturally wear away as you mow.

That said, "generally fine" isn't the same as "always fine", and you should still inspect new lawn mower blades. Observe the blade for any damage, cracks, nicks or bends. If there are any, replace the lawn mower blades instead of immediately trying to sharpen them to fix the damage. Also, do not judge the blade just by touching its edge with your bare fingers. Instead, look at how it mows. You need to watch the lawn closely after the first cut and see if the grass is cut clean or if it has torn blades.

A properly sharpened blade leaves a clean cut, whereas a dull blade tends to tear and fray the grass instead. So, if you notice torn or frayed grass and the blade edge also feels particularly thick, then there is a good chance that your new lawn mower blades need sharpening. When sharpening, make sure that you follow the existing bevel and do not over sharpen your lawn mower blades. Plus, balance the mower blade after sharpening. Otherwise, your lawn mower will vibrate when you mow, and it will ruin your whole mowing experience.