Do New John Deere Mower Blades Need Sharpening? (Solved & Explained!)

No, new John Deere mower blades do not need to be sharpened or balanced. These blades come pre-sharpened and balanced, right ‘out of the box’, and are ready for immediate installation and use if you should choose to do so. It is a good idea, however, to feel the current edge as a reference, as you will need to sharpen them after the first 20 – 25 hours of use.

For the remainder of this article, we’ll tell you more about sharpening for different blades, how sharp is too sharp, what it costs for professional sharpening, and more! Let’s look at the most common questions that people are asking about mower blades and their maintenance!

What angle do you sharpen a John Deere mower blade?

You will want to sharpen your John Deere blade with a whetstone or file measuring approximately 10 inches in length at an angle of 45 degrees. This is fairly standard for John Deere blades, but if you want to doublecheck, simple hold the file against the existing angle and this is perfect for sharpening.

Follow this by sharpening from the top side of the edge in the direction that bites the steel.

Are you supposed to sharpen new lawn mower blades?

No, most mower blades will come from the factory pre-sharpened and balanced and all that you need to do is install them and they are ready to use. While there are exceptions, this is quite uncommon. Before installation, check the edge for future reference, as you’ll need to sharpen them aftertwenty to 25 hours of use.

How do I know if my lawn mower blades need sharpening?

Uneven cutting, tipping of grass, brown spots that develop quickly after mowing, or visible dents and dings in the blade are all signs that it’s time to sharpen your blade. In most cases, a regular schedule of sharpening every twenty to twenty-five will suffice, but you should always check if you run over something just to be sure.

Do new mower blades need balanced?

No, you do not need to balance new mower blades as they will come pre-sharpened, balanced, and ready to use.

You will want to sharpen and balance them after the first 20 to 25 hours of use and you can do this on your own by clamping it in a vise and sharpening with a whetstone, file, or angle grinder, or you can simply bring them in and your local hardware store will sharpen them for a small fee.

Do mulching blades need to be sharpened?

Yes. Mulching blades can dull like any other blades and should be sharpened on the same schedule that you would with a standard blade. This means that for every 20 to 25 hours of use, your mulching blades should be cleaned, removed, and sharpened, to be followed by balancing the blade.

This will help ensure that your cuts stay clean and that you get the most working life out of your blade.

How much does it cost to have lawn mower blades sharpened?

It depends a lot on the make and model of blade and the vendor that you chose. That said, most hardware stores will sharpen a standard, 21 inch regular or mulching blade for approximately $5 to $15, while riding mower blades or 42” twin blades from larger deck mowers will generally range from $20 to $60 for balancing and sharpening services.

Are mower blades universal?

No. You always want to check compatibility with your specific make and model of mower before you purchase new blades. Mower blades are designed for specific mowers and while some may be compatible with others, you’ll definitely need to check.

 Some have different hole shapes for attachment, different lengths, or blade shapes, so they’ll need to be compatible with you deck, means of attachment, and engine power (for heavier or high-speed blades).

How often should lawn mower blades be replaced?

Lawn mower blades should be replaced every year or after approximately one to two-hundred hours of work use. Some blades will have a longer operational life, due to the inclusion of harder metals or other additives, so if you purchase a specialty blade then check your documentation.

Some of these higher end blades can last up to 400 hours, provided they are kept clean, sharpened regularly, and the terrain where they are used is fairly flat and prone to damage the blades.

Can I sharpen my own lawn mower blade?

Yes, you can definitely sharpen your own mower blade. You’ll need a vise to clamp the blade in place and you can then sharpen it with files, a whetstone, a bench grinder, or an angle grinder.

 Angle grinders are fairly inexpensive, so a good way to make short work of sharpening is to invest in one (you can usually get a small handheld for less than $60) and use this to sharpen your mower blades and other DIY tools that require it from time to time.

Can a lawn mower blade be too sharp?

Yes, mower blades can easily be oversharpened and it is a common mistake. While a razor sharp mower blade will perform quite well for a few minutes, it will dull more quickly and then the thinned-out steel means that your blade may be damaged more easily and will need to be replaced sooner.

Try to sharpen to the same factory-edge that it came with when you purchased it or if you aren’t certain, go for the same edge that you’d find on your average butter knife.

What’s the difference between mulching blades and regular blades?

Standard blades tend to have a single cutting edge and a rectangular shape, while mulching blades have extra cutting edges, as well as upward-facing ‘teeth’ for mulching leaves, and additional curvature to the blade.

John Deere may be the only exception, as they do have rectangular mulching blades, but this is the only instance we are aware of where the mulching blades are not curved.