I have a Ryobi electric lawnmower, and I want to get the blade sharpened for the first time. I have a 15mm ratchet wrench, just like the instructions say, and I'm immobilizing the blade with a brick.

But no matter how hard I turn, the bolt just doesn't budge at all. I called Ryobi support, and they said the only other thing to try was spraying the bolt with WD-40. I assume the bolt is so tight because it hasn't been touched since being assembled at the factory.

I did that, let the WD-40 sit for a half hour, and tried again. The bolt still won't budge at all. What are my other options? I don't own an impact wrench.

  • 2
    Try cleaning the lawn masses off it and using penetrating oil. hint: WD-40 isn't penetrating oil, it's water-displacing oil hence WD. This is a common misconception which comes from WD-40's intense efforts to market their product as a do-everything oil. May 20, 2017 at 0:53
  • @Harper Thanks! This did the trick. I bought some PB penetrating oil, let it sit, and then the bolt came off. If you post this as an answer, I'll accept it.
    – Bill
    Jun 14, 2017 at 14:27

4 Answers 4


Allowing for the inherent mechanical weaknesses of a ratchet wrench and the limited lever arm provided by such a short handle, consider to purchase or borrow a 15 mm box end wrench. The handle may not be much longer than the ratchet wrench, but will more safely accept a lever extension.

A strong steel pipe of a meter length or better, with an inside diameter to accept the box end wrench will give you an incredible lever arm.

If you are confident that you are turning the bolt in the correct direction and that it is designed to be removed in this manner, you are likely to free it up easily. If not, it's also possible to snap the head right off, or worse, break something internally.

Your local mower shop may also accept the mower and have the necessary tools to pull the blade. You may have to pay a bit more for the first time, but it's also likely it won't be as difficult to remove the next time.

  • 1
    An impact wrench will make all the difference in the world, and obviate the need to hold the blade, since the impact will land faster than the blade can turn. May 20, 2017 at 0:54
  • A breaker bar is designed for this exact scenario where you need more torque than a little standard-size wrench is going to provide.
    – Bitmapped
    Dec 26, 2022 at 1:09

There's a tool I bought that attaches to the side of the mower to hold the blade in place. Not only does it to a far better job of holding the blade, it tends to fare better in torquing

The only other thing I could suggest is turn the unit on its side (be careful of the oil if it's a 4 cycle gas) and see if you can get better leverage with your wrench

  • Thanks! Do you know the name of the blade holder?
    – Bill
    May 20, 2017 at 2:57
  • I just Googled "lawnmower blade holder". There's several brands
    – Machavity
    May 20, 2017 at 4:17
  • 1
    I just googled "3 inch pipe" LOL. May 20, 2017 at 13:31

There are some other very good answers already posted but here is another.

  • Make sure it is not a reverse thread nut. I expect that to be the case Ryobi should know this.
  • Using a socket that fits over the ratchet handle you can easily add torque by inserting a socket into the extension thus making the equivalent of a pipe extension , just in case you are as cheap as me and don't want to buy a piece of pipe.
  • Get a propane torch heat the nut area up, quickly place your socket over the nut and loosen ..
  • Just a caution on the torch... the underside is coated with dry grass. You might set something on fire doing that
    – Machavity
    May 20, 2017 at 13:33

The blade bolt may be of a small enough size that putting a "cheater pipe" on it or using a longer ratchet or "breaker bar" will just sheer the bolt off. It is possible that the bolt has rusted a bit in place or that it was placed at the factory with "thread cement".

In either case my strategy is, if everything around it is metal and won't be damaged by flame/heat, is to use a propane torch (a good one, maybe even a "MAPP" gas torch) to heat the bolt until a few drops of water will sizzle on it, and then cool it with water. Then reheat it, and cool it. Do that 3 to 6 times and the combined expansion and contraction will usually free up the threads. If in fact there is thread cement on it, then after a few heat/cool cycles, try taking it off while it is still hot.

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