How To Tighten Lawn Mower Blade
Lawn mower | Guides

How Tight Should Lawn Mower Blades Be


Are Lawn mower blades supposed to be loose or tight?

It’s a common question from lawn owners, especially beginners.

Most of us think that the blade should be tight up to its maximum capacity.

Please read the mower’s instructions guide to leave you surprised because it suggests the edge should be a bit loose.

Now you might be wondering, are mowers blades need to be loose for better performance? If yes, then how flexible will be perfect?

Here’s the deal.

It would be best if you tightened the blade up to the extent that it does not move at its will. However, the edge should move if you apply some physical force. You can find the right tightening level in the manufacturer’s manual. It is generally mentioned in foot-pounds.

But, there is more than meets your eye in this case because all the mowers are different. Let’s know more about this topic here. We have collected some of the most common questions and their answers, which helps if you are new to lawn mowing.

How Tight Should a Lawn Mower Blade Be?


The answer depends upon the make and model of your mower. Plus, the type of blade also determines how tight it should be. Some of the manufacturers suggest that you should keep the edges as fast as possible. However, some brands recommend keeping it a little loose.

Some of the mowers have special functions so that the blade can rotate even if you tighten it completely. The manufacturer’s manual will provide all the information related to this topic. If you don’t have access to it anymore, try to find an online manual from the brand’s website. You can also consult customer support or shop from where you purchased the mower.

As we discussed before, you can find the proper torque to tighten the blade bolts in foot-pounds or ft./lb. Unfortunately, you cannot measure it without referring to the guide. But yes, a torque wrench that can apply the required pressure to bolts and screws.

Some of us might not know about this tool. So, browse Amazon and purchase a torque wrench. Tekton 24335 is one of the best because of its steel construction and calibrations that can suit the manufacturer’s torque specifications.

How To Tighten Lawn Mower Blade?


Should Lawn Mower Blades Be Loose

A lawnmower with loose blades is unsafe to use. Plus, it can damage the internal components of your mower as well. So, you should make sure that the blade is fastened adequately to its bolt. Use a torque wrench for this task because it shows the exact foot-pounds of required pressure.

  • Park the mower to a flat surface. Please turn off the machine and take out its spark plug. In case you have an electric model, remove its battery or unplug its power cable, depending upon the power type.
  • Drain the fuel from your mower. Do not leave even a bit of petrol inside its tank.
  • Wear leather gloves and tip the mower on one of its sides. Make sure its oil tube faces the sky. The oil tube is near the oil cap, where you check for oil.
  • We recommend that you place a 2 x 4-inch wooden block between the blade’s back and mower’s bottom. This block will not allow the edge to move while you tighten it.
  • Attach a socket with the torque wrench so that it can fit the bolt properly. A 9/16-inch socket works on most of the lawnmowers. Look for 30 foot-pounds on the wrench and adjust. Follow the measurements provided in the instructions manual.
  • Use one of your hand to hold the blade’s one end and put the correct socket on the wrench. Tighten the bolt using the wrench. Keep moving the wrench until it clicks. The clicking sound means that the pressure is set to 30 foot-pounds now.
  • Remove the wooden block and try to use the mower.

Can You Over Tighten A Lawn Mower Blade?


Over-tightening the blade might damage it. For instance, the edge will instantly break after hitting a solid object if it’s extra tight. The bolt holding the sword and all its washers might fail as well. It’s simple to understand; excess pressure is breaking the bolt’s neck.

Don’t be assured that the blades are not over-tightened in case its bolt is not breaking. Every time you over-compress the bolts, it’s threading gets deformed a bit.

Keep repeating the same, and the blade will not even stay in its place after some time. It would be best if you did not over tighten a mower blade because it creates a lot of trouble.

What To Do If The Mower Blade Won’t Tighten?


Over tightening the bolts multiple times might be the reason. As we discussed before, over compressing the bolts will deform its threads, and after some time, it will not be able to hold the blade properly.

The solution is to purchase a new mower blade bolt. Almost all the manufacturers sell replacement bolts for their mowers. So, finding such a component will not be complicated or expensive. Make sure you purchase something compatible.

Replacement is the only solution because you cannot repair a deformed bolt. It’s the reason you should avoid overtightening the blade.

Can A Lawnmower Blade Spin Freely?


Can A Lawnmower Blade Spin Freely

If the lawn mower blade spins freely, then there could be multiple reasons behind it. First, the edge could be loose. So, you need to try and tighten it. If the problem remains, then there could be something else. Read on to know more.

Reasons why the mower blade loses its grip.

Sometimes a blade doesn’t want to stay on its bolts. No matter how much efforts you apply to tighten the blade. Do you know why? Let’s discuss the reasons.

  • Over-tightened bolt: As we stated above, repeated over tightening of the blade would damage its bolts. So, it will not hold the edges. Replacing the bolt is the only solution.
  • Loose bolt: The mower blade loses its grip if its bolt is not tightened correctly. It happens when you are very cautious while pulling the knife. We recommend that you apply the required pressure but do not apply extra force. The best way is to use a torque wrench and follow the mower manual.
  • Deformed Blade: The blade can lose its shape after hitting some solid object like a sidewalk. You will not be able to tighten a knife that has lost its form. A disfigured blade will also interfere with the mower’s cutting performance. Even if you somehow manage to tighten the bolt, it will loosen within some time. So, replacing the blade is the right solution because it’s doubtful that you can fix a bent blade.
  • Unbalanced blade: An uneven sharpening might imbalance the blade. So, if you recently sharpened the mower, test it on the mower blade balancer. Place the blade on top of the balancer. If you notice any disparity, sharpen the heavier edge to take out some of its weight.

Final talk


A lawnmower with a loose or over tighten blade will not cut efficiently. None of its internal components can do anything if the blade is not spinning correctly.

And it’s easy to understand because only an edge can cut the grasses. So, you should tighten the blade if it’s moving freely even after you engage the controls.

Last Updated on March 24, 2021

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