Are Lawnmower Blades Supposed to be Loose? | How to Fix

Are Lawnmower Blades Supposed to be Loose

There is nothing worse than turning on your lawnmower to hear an unfamiliar sound from underneath it. Upon turning over the lawnmower, you find out that your blades have loosened from the lawnmower. Lawnmower blades that are loose present a magnitude of utility and safety problems.

A loose lawnmower blade is not only useless when it comes to attempting to mow your lawn, but they are also dangerous. A loose blade can end up hurting your or the mower if left unattended. The good news is that they are often easy to identify and fix once you know the problem.

In most cases, a loose lawnmower blade is something that the average lawnmower owner can fix. The key is to know what to look for, how to fix it, and to know when you may need professional help or even a new blade. Let’s talk about potential reasons why your blade may come loose, what to look for, and how to fix it.

Are Lawnmower Blades Supposed to be Loose?

A loose blade on a lawnmower is never a good thing. Loose blades can make your job much more difficult if you are trying to cut your lawn. They are not going to cut as well as a stable and secure blade, but you also need to be aware of the dangers if left unfixed. Loose blades can break off and cause damage to your lawnmower, and even in some cases, yourself.

If you hear a rattling sound coming from underneath your lawnmower, you may have a loose blade. Once you notice that sound, your first step should be to turn off your lawnmower and tighten your blades before you try to use it again. Additionally, your lawnmower blade should never be spinning or moving freely. These blades are designed to work with the motor they are attached to. It is an excellent habit to routinely check your lawnmower blades to make sure they are working.

If you end up having loose blades, they can usually be fixed in a matter of minutes. You should be able to use a wrench in order to tighten the blade, but make sure you take proper safety precautions so that you do not end up cutting yourself. You want the blades to be just tight enough to be secure without overtightening. If you are still having blade problems even after you tighten it back, it may be time for a new blade.

On the opposite end, you can actually overtighten the blades of your lawnmower. A blade that is too tight can damage the blade, or even completely break it away from itself or the mower. Since the overtightening will occur at the bolt, the bolt itself could also be damaged if you run over something too hard, or if debris flies up while you are mowing. A common rule of thumb is to tighten your blade until it is secure, but you should avoid using intense pressure to tighten the bolt.

How to Fix a Loose Lawnmower Blade

No matter what kind of lawnmower you have, a loose blade is an easy fix. While fixing both standing and riding lawnmowers, make sure you are taking the necessary precautions to keep yourself safe.

Before you decide to do any work on your lawnmower, you want to make sure that you are protecting yourself and the machine before you begin. Gloves should be used to protect your hands from grease and debris and sharp blade. The spark plug should be removed entirely from the lawnmower before attempting any repairs. The machine could turn on while you are trying to fix it.

Standing Lawnmower

  • Place your lawnmower on its side with the oil cap facing upward.
  • Using a wooden block, place the block against the lawnmower’s deck to prevent the blade from trying to move while you tighten the bolt for the blade.
  • Using a wrench, tighten the bolt for your lawnmower blade. Most owners use a torque wrench so that they can adjust it to a specific setting, often 30-foot pounds.
  • While wearing a pair of gloves, hold the blade in place while you adjust the bolt.
  • Place the lawnmower upright, replace the sparkplug, and test your lawnmower.

Riding Lawnmower

  • In a flat area, raise the deck of your lawnmower to the highest setting.
  • After turning off your mower, find the blade you are looking to tighten and hold on to it while wearing a pair of gloves.
  • Using a torque wrench, tighten the bolt on the blade.
  • Repeat on the other side of the lawnmower if necessary. Make sure your torque wrench is in the same setting for both sides of the lawnmower.

What Can Cause a Lawnmower Blade to Come Loose?

Your lawnmower blades should spin without touching any part of the lawnmower and without making any metallic sounds. Sometimes the case of a loose blade may be as simple as the blade or the ball bearings are worn out and need to be replaced. For those who do not have a habit of checking your blades, here are some reasons why you may end up with a loose lawnmower blade.

Even if your lawnmower is in the best condition possible, a loose blade can occur for a number of reasons. The most obvious reason being that you may have accidentally hit or ran over something while you were mowing. The best way to avoid this is by observing your mowing area while you have your lawnmower out. If you see any rocks or debris, make sure you are picking that up before it comes in contact with your lawnmower.

There may also be something wrong with your blade. Older blades can become deformed after repeated use, especially if you have a tendency to run over items in your yard. Checking your blade before you mow, or at least once every few weeks can make sure your blade is still in good condition. Checking your blade can help ensure that your blade is in the correction position at all times as well.

If you are using a new blade and notice it becoming loose more often than it should, there may be a problem with the blade’s installation. Most blade adapters use a key that needs to be in the adapter’s slot in order for the blade to be stabilized. When you are fixing your blade, make sure that the key is not broken, and that it is located within the adapter itself.

Final Thoughts

Your lawnmower blades should never be loose or spinning freely. As long as you take proper care of your lawnmower, loose blades are not something you are going to have to deal with on a regular basis. Even though they can be a pain, fixing them is relatively easy and will usually get your lawnmower back on the lawn. It is important to remember that lawnmower blades are incredibly sharp, so taking the necessary safety precautions is the best way to avoid damaging your lawnmower or injuring yourself.

Lawnmower blades that become loose are often a sign of maintenance. Your lawnmower blade may be ready to replace, or there may have been some sort of accident while you are mowing. When you are doing regular maintenance on your lawnmower, such as replacing fluids, take the time to check your blades to make sure they are in working order. A torque wrench and a wooden block will help you make sure your blade is tightened correctly.



I’ve been working in the lawn care business for 15 years. With this blog, I hope to share with you my experience and recommend the best lawn mowers on the market.

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