Rotary mower blade bolts. Are Lawn Mower Blades Reverse Thread? Essential Information

Are Lawn Mower Blades Reverse Thread? Essential Information

“ Are lawn mower blades reverse thread? ” is something you might have asked yourself when checking your lawnmower blades.

Our complete guide will help you determine if you have reverse threaded blades and give you other essential lawn mower blade tips and techniques.

Do All Lawnmower Blades Have Reverse Threads?

No, not all lawnmower blades have reverse threads. Typically, the phrase does not refer to your mower blade but rather to the bolt that holds it in place. The bolt is an essential piece of your lawn mower that connects the blade to the driveshaft.

Some lawn mower blades have bolts with reverse thread as their blades go in the opposite direction. The mower blade rotates to cut the grass, so a secure hold is important to keep the operation safe and should be as free from possible risks for injury as possible. The blades are already balanced but it is important to know how to balance your lawn mower’s blades on your own.

A bolt can be threaded in the standard direction or in reverse. The same goes for the mower blade. Mower bolts and blades usually are in different directions when it comes to their threads in order to keep both from becoming loose and coming off the mower.

Knowing the direction of your mower blade bolts is important so that you can easily unscrew the bolts for a replacement blade or to fix the current blade. While many mowers have reverse threads, not all will have this feature.

Why Only Some Bolts Are Reverse Threaded?

Based on the list of the most common and popular brands, you can quickly determine that not all mulching blades have bolts with reverse threads. In fact, most are threaded in the standard direction and not reverse threaded.

Remember that manufacturers design and develop their products for very specific reasons, so mowers with reverse thread bolts are not always better than others.

Given that most manufacturers produce lawn mower models with their blades reverse thread. it’s only fitting that their bolts tighten and loosen in the traditional manner. If the bolts were threaded in the same direction as the blade, operating the lawn mower could become highly dangerous.

Having the lawnmower blade and the bolt in the same direction can cause the bolt to loosen easily. This can cause serious injuries to lawn mower operators if the blades were to come loose as the mower blades turn.

By designing the mower blades reverse with the bolt’s thread direction, there is less possibility of the bolt loosening from the mower blade. However, if your goal in learning about the thread direction of your bolt and blade is to remove them for replacement, then continue reading.

– Removing Reverse Thread Blades

likely than not, you’re cautious and curious about the thread direction of your mower blade and its bolt because you want to check if it needs replacement. Or you might be curious if the nut and bolt have deteriorated, and you don’t know which way to turn the bolt.

Either way, you might need to remove the mower blade eventually, and this short guide can help you make fast work of the bolt and blade thread direction.

Here are the steps you need to do:

  • Wear personal protective clothing such as gloves, goggles, and clothes. This will keep you from getting injuries from any untoward incidents.
  • For gas-powered models, disconnect the ignition wire that is connected to the spark plug. For cordless mowers, take out the battery pack to prevent the engine from powering up accidentally. This precaution is important to avoid sudden starts that can highly compromise safety.
  • Tilt the mower on one side. Make sure that the air cleaner and gas tank are facing upward so that you’ll avoid spillage that may reach the nut or bolt of your mower blade.
  • Keep the blade from moving around by wedging a piece of wood between the inside of the mowing deck and the end of the blade.
  • Use a socket and wrench to loosen the nut or bolt of your mower blade. You can even slip on a long bar over the handle of the wrench if you want to increase your turning leverage.
  • Make note of the lawn mower blade position in terms of which side faces downward. This is vital as it will indicate the direction once you bolt the mower blade back in position.
  • Loosen the bolt, depending on the thread direction, and remove the blade. Make sure that you use the right socket-size wrench.
  • Make sure you have your gloves on when removing and replacing the lawn mower blade. Work in a methodical way so that removing and replacing your lawn mower blade will be as efficient as possible.

Once you’re done removing and replacing your lawnmower blade, you can begin putting everything back. If you have trouble remembering, refer to the quick guide but in reverse order.

How Do You Determine Reverse Thread Bolts and Blades?

To determine reverse thread bolts and blades, you may need to check your owner’s manual given that not all mower blades have threads that are reversed. This is the most effective way to determine the thread direction of your blade.

However, if you no longer have the owner’s manual, you can always look up the brand, make, and model of your lawn mower. This will also help you in finding out the thread direction of your blade.

You can also refer to our list of brands that commonly have mower bolts with reverse threads, which are found below. We’ve also included brands that do not have reverse threads for your convenience.

– Craftsman Mower Blades

The Craftsman mower blade usually has bolts that are reversely threaded and blades that are threaded in the standard direction.

To tighten the blade bolt. turn it counterclockwise to the left. To loosen the bolt, you’ll need to turn it clockwise to the right.

– Cub Cadet Mower Blades

Most, if not all, mowers of this brand have bolts that are threaded in the normal direction, with blades in the reverse thread direction. This means that you’ll have to turn the bolt clockwise to the right to tighten it or turn the bolt counterclockwise to the left to loosen it.

– John Deere Mower Blades

This brand does not usually have reverse thread bolts, which means that the blades are reverse-threaded. The bolts are often found threaded in the typical fashion. In order to tighten the bolt, turn it clockwise to the right. To loosen the bolt, turn it counterclockwise to the left.

– Toro Mower Blades

Bolts that fasten the sharp blade of this brand tend to have threads in the traditional direction, with blades in the reverse thread direction.

This means that you’ll need to turn the bolt clockwise to the right to tighten it and counterclockwise to the left to loosen it.


A lawn mower can have reverse thread directions when it comes to its mower blade and bolt.

rotary, mower, blade, bolts

Concern about mower blades reverse thread can be alleviated by remembering this recap:

  • Not all lawnmower blades have reverse threads, which refer to the bolts that hold the blades in place.
  • Reverse thread can refer to both the mower blade and the bolt thread direction.
  • Typically, mower blades reverse in direction with the bolt to keep everything tight, secure, and safe.
  • Most mowers have their bolt directions in the standard fashion because the blades are often reverse thread.
  • When removing or replacing lawn mower blades, always wear protective clothing.

Knowing the thread direction of your lawn mower blades and bolts is crucial, especially when you’re removing the blades or simply doing preventive maintenance. Lawn mower blade maintenance is also extremely crucial and you should know how often to do it. Now that you know how to check the thread direction of both parts, tell us how this article helped you!

Are Lawn Mower Blades Reverse Threaded?

Lawnmowers are excellent garden or outdoor tools that help lawn owners to maintain their lawns and cut grass neatly. Just like any machine that you’ll find, lawnmowers also require regular care and maintenance, and removing the mower’s blade for the purpose of sharpening or replacement is one of the major maintenance tasks.

Typically, most blades found on walk-behind lawnmower models are held in place by a threaded hex-headed bolt that screws into a blade adapter fitted onto the engine’s driveshaft. Whenever your mower blade needs to be sharpened or replaced, it is necessary that you turn out the blade retaining bolt in order to get the blade off the mower.

Are Lawn Mower Blades Reverse Threaded?

Yes and no. The lawnmower blades itself is not threaded, but most nuts that held the blade in place are reverse threaded. The reverse thread helps to secure the blade on the drive shaft such that the rotation of the blade does not loosen the nut. It is important to note that not all lawnmowers use a reverse threaded nut.

There are still a lot of details to pay attention to in order to carry out the procedure easily and correctly. In this article, we’ll be showing you the complete step by step process on how to do it safely. It’s safe to say that the last thing anyone would want is to be in a hurry to quickly get the blade off, only to end up injuring themselves. This actually happens more than you may think. Follow closely in the rest of this article to find out all you need to know about this topic.

How Do Lawnmower Blades Work?

One of the most interesting features of lawn mowers is undoubtedly their blades which are responsible for cutting the grass neatly. Also, these blades are the major feature that catches our attention when we’re purchasing the equipment or when we consider a functioning lawn mower. So it is quite obvious why the blades are very important and have become a topic which many pay close attention to. In fact, you’ll find various thesis about the blades, and why their incorporation to the internal combustion engine has become very vital in differentiating the different types of lawn mower that there are.

That being said, threading is a crucial aspect that helps in the movement and rotation of the blades. For all such rotating objects generally, the threading is designed in such a way that every rotation tightens the nut to ensure that the blade remains firmly attached and intact with the frame. It simply works by turning the center of the blade opposite to the normal cutting rotation. There is a securing nut that is specifically provided for this purpose. It is also important to note that loosening refers to a right-hand thread which is done in the clockwise direction while tightening is the left-hand thread which is done in a counter-clockwise direction.

Are Lawn Mower Blades Reverse Threaded?

Generally speaking, most lawnmower blade nuts are reversely threaded to firmly secure the blade onto the drive shaft of the engine. This simply means that when the blade rotates, the bolt is not loosened or affected. It is worth remembering that not all blades are designed with a reverse thread bolt to secure them. So when you want to sharpen or replace your mower blade, it is important that you first find out the direction of shaft rotation. By doing this, you’ll be sure that the blade’s rotation won’t end up loosening the nut.

You’ll find that the blades on many walk-behind lawn mower models rotate to the right when you are mowing (that is, the clockwise direction). To remove the blade on this type of mower, the blade’s retaining bolt should be turned to the left or counterclockwise direction. Before unbolting your blade, make sure you tip the mower on its side with the engine air cleaner facing upward, then block the blade with a piece of wood so it won’t turn while you’re working. Also, make sure the bolt is kept in a safe place so that you can easily locate it when it’s time to return the blade.

Most times, the blades of a lawn mower are reverse-threaded. However, you may be required to block the blade from turning in order to break the bolt loose. Removing your blade for sharpening or replacement will require the use of a socket wrench to unbolt the lock nut, which is often reverse-threaded. Also, it is important to follow the safety instructions for your particular lawn mower which is usually found in your user manual. Wear protective gloves to shield your hands from cut or injury, and follow all instructions properly.

How to Remove the Blade Safely

Step 1. Disconnect the ignition wire:

The first thing to do is to disconnect the ignition wire from the spark plug. If you’re using a cordless mower, remove the battery pack. This is to prevent the risk of the engine accidentally starting up while you’re working. You should also drain the gas tank so it won’t spill any fuel while you’re working on the blades. To disconnect the spark plug, locate the spark plug boot, which is usually found on the front side of the engine. Firmly pull the boot to disconnect it from the spark plug. No extra tools are needed for this step as you can simply use your hand.

Step 2. Tip the mower:

Tip the mower on its side, with gas tank and air cleaner facing upward in order to prevent spillage, and to expose the nut or bolt that secures the blade to the mower.

Step 3. Retain the blade from moving:

Wedge a short wood block between the end of the blade and inside surface of the mowing deck to keep the blade from turning accidentally. Then use a wrench and socket to loosen the nut or bolt. To increase the leverage when loosening any stubborn fastener, you can slip a longer bar over the wrench handle.

Step 4. Note the blade position:

Remember to make a mental note of which side of the blade faces downward. It’s important to bolt back the blade in the same position as it was removed. When breaking the bolt loose, you may need to apply a bit of force, but be sure that you don’t slip and cut your hand. Using a breaker bar will help provide an extra force while safely loosing the bolt.

Step 5. Remove the blade:

Loosen the bolt by turning left (counterclockwise) using a 16mm socket. However, depending on the model of your lawn mower, the bolt head can be 1/2″ inch or 5/8 inch.

To have more leverage, you should make use of a bigger socket wrench. As you turn the socket, the blade bolt will also turn, although you may be required to hold it with your hand while loosening it. This is why it is important to wear gloves while working to protect your hands from injury. It is also worth noting that some models of lawn mowers use a blade-lock tool to keep the mower in one place. These tools will prevent the blade from rotating when you’re trying to remove the bolt.

It is not uncommon to see the nut get smaller due to corrosion, hence, you should make use of an appropriate tool. For instance, a 16 mm socket may be a better fit for an 18 to 20 mm bolt due to the reduction in size. Next, you should look for a breaker bar to help with leverage. If you notice that the tension suddenly becomes soft, it may be the bolt stripping the threads and not that it is loosening. This is why the wearing of gloves should be taken seriously to reduce skinned knuckles. Finally, be sure to fit the replacement blade into the blade adapter, making sure that only the correct side is facing up. Also, replace the washers in the right order. Then tighten the blade retaining bolt by turning it clockwise or to the right, using the torque value that is specified in your user manual. We hope that this piece has been helpful. Good luck.

Step 6. Clean the Mower underside:

This step is optional, but once the blade is removed, try to scrape clean the underside of the mowing deck to remove all caked-on debris and grass. You can use a narrow-blade putty knife to get better results.

How To Remove Stripped Bolt From Lawn Mower Blade?

Do your lawn mower blades have completed their lifespan, and now they need replacement? But you are unable to replace it because of a stripped bolt. Yes, you cannot replace the blades until you win the war against the blade bolt. The basic ideas about removing stripped bolts from lawnmower blades are a huge help. But do you know basics of the how to remove stripped bolt from lawn mower blade?

You have several ways to remove the stripped bolt from the blade. For smaller lawn mower blade bolts, use a hammer and punch. If the large bolt is stripped, use an impact wrench and socket to remove the bolt.

However, you need detailed information to perfectly complete this job. We recommend you read the content below to learn the safest ways to remove stripped bolts from lawn mower blades.

Methods to Remove Stripped Bolt from Lawn Mower Blade:

You may find several ways to remove the stripped bolts from the lawn mower blade. But when it comes to simple and effective ways, very few of them meet the criteria.

Here we have listed the two easiest methods that may help you to remove the bolt from the blades of each lawn mower model.

How to Off the Bolt from the Lawn Mower Blade? (Simple Solutions with 2 Easy Methods)

It will be irritating when you cannot replace the blades because of the tiny bolt. You need quick solutions to remove the bolt to continue your job.

Things You Will Need:

For both of the methods, you will need the following tools:

  • Hammer
  • Punch
  • Wrench
  • Extension Bar
  • Beam
  • Socket ( 24mm)
  • Long hollow metal pipe
  • Metal Block

Method 1: Remove Bolt Using Socket and Impact Wrench

To make your job easier, buy Olympia Tools Adjustable Wrench. It is inexpensive but straightforward to apply for bolt removal jobs.

Step 1- Fix the Lawnmower to Protect it From Moving

First, you will need to fix the lawn mower at a place where you can protect it from moving. You can use the beam, jack, block and breaker bar, or anything else to keep the lawn mower in place while applying force.

Step 2- Attach the Socket and Impact Wrench

Take the 24 mm socket and then attach the impact wrench with the socket. See the threads side; you will need to turn it clockwise. For the clockwise, adjust it left-handed.

If your bolt size differs from mine, you may need another size instead of 24mm.

Step 3- Attach the long Pipe.

Then take a long hollow metal pipe to attach it with the long wrench. Taking a hollow pipe with little more than the wrench diameter will be good. It will provide more control over the wrench to perform the functions.

Step 4- Use the Metal Block to Support the Lawn Mower.

Now take the metal block and use it from the side to give excellent support to the lawn mower to protect it from moving.

Step 5- Set the Socket Onto the Bolt.

Then take the wrench attached to the long pipe and set the front end socket on the bolt. Make sure it is correctly adjusted on the bolt. Confirm it by applying a little force.

Step 6- Loosen the Bolt.

Now apply force and try to rotate the bolt clockwise. It may take two to three pulls.

Step 7- Off the Bolt from the Blade

Once the bolt is loose, you can easily get it off the blade. Remove the pipe and rotate the wrench clockwise. After a few turns, you will remove the bolt from the lawn mower blade.

You Can Watch This video, This video shows you how to Remove Stripped Bolt From Lawn Mower Blade:

If you see corrosion, you should remove it with a brush. It will ease you to access the bolt.

Step 2- Put the Punch on the Bolt.

Then take a smaller size punch and put it over the bolt. It will help you to hit the bolt to loosen it.

Step 3- Push the Punch With a Hammer.

Then hit the punch with the hammer. Please do not hit it too hard; it may damage the bolt. Hit it a few times. You will see it will become loose after four to five hits.

Step 4- Rotate the Bolt With a Punch.

Now, keep the hammer aside and try to rotate the bolt with the punch.

Step 5- Rotate the Bolt with Your Hands.

Once it is enough to loosen, you can rotate it with your hands. Rotate the broken stripped bolt with your fingers clockwise to remove it from the blade.

Step 6- Remove the Bolt.

After a few clockwise turns, you can remove the stripped bolt.

Why does the Lawn Mower Blade bolt Get Stuck?

A few major reasons for a lawn mower blade bolt to get stuck can be:

It may get stuck because of corrosion

Grass or debris residuals may also cause it to be stuck

Broken bolts also stuck when hit with something

What are Helpful Tips for the Easy Removal of Lawn Mower Blade Bolts?

Whatever bolt removal method you use to remove the bolt from a lawn mower blade, it is a must to take the following steps before starting your job.

Make sure the lawn mower spark plug is disconnected

Ensure you have drained the oil and fuel properly

Before accessing the bolt, clean it and ensure you have removed debris and corrosion, etc.

Frequently Asked Questions (FAQs):

Are all lawn mowers blade bolts reverse threaded?

Yes, all of the mowers have reverse thread bolts with their blades. You need to move it counterclockwise to tighten the bolts and loosen the lawn mower blade clockwise.

What size is the lawn mower blade bolt?

Most lawn mower blade bolts are 5/8” inches in diameter. You will need 15/16” socket or wrench tools to remove the bolts.

Do I need an impact wrench for the lawn mower blade bolt removal job?

rotary, mower, blade, bolts

Having an impact wrench for the lawn mower blade bolt is not essential. But it will be very simple if you have a high torque impact wrench.

rotary, mower, blade, bolts

How often should I replace the lawn mower blades?

Generally, the lawn mower blades have a one-year lifespan. You can replace them annually. But if there is a problem such as blade damage because of hitting something, you will need to replace it for a smooth mowing experience.

Final Verdict

Lawn mower blades are attached with the bolts. It is essential to remove the bolt to access the blade. But if it is stuck, you will need special treatment to remove the bolt. Once you have removed the bolt, it will be easier to replace the blade.

However, I recommend you to take care to protect your lawn mower blade bolt from stripping. Ensure cleaning and careful riding to keep bolt removal jobs easier.


Lawn Mower Blade Bolt Stuck – Mechanics secret tips

I know the feeling, FRUSTRATION. but we’ll get it figured out. The blade bolt can be stuck for a few different reasons. Usually, it’s a combination of rust and over-tightening.

The easiest way to remove a stuck blade bolt is with an impact tool; they make the whole job look easy. Other options include:

You may not have an impact, so I’ll show you a few different options. Some of these options may not suit you; it’ll depend on what tools you have available. Best to don a pair of work gloves. Stuck bolts usually mean slipping tools.

Removing A Rounded Bolt

Over-tightening is common. Mower blades are designed to be tightened to a specific torque, which isn’t as tight as you might expect. That’s because they’re designed to slip if they hit a solid object. The slipping protects the engine from serious damage associated with a curbstone strike.

Also common is turning the bolt the wrong way; hey, it could happen to a bishop. All single-blade walk-behind mowers will have what’s known as a right-hand thread. That means, to loosen the bolt, you turn it to the left. (counter-clockwise)

Easy Quick and Safe Way to Remove Mower Blades

I cover all you need to know pretty well in this post, but if you need more help, check out the following videos:

Blade Bolt Torque

Mower blade bolts should be torqued to spec. These bolts are usually over-tightened, and when you add corrosion, removing them can be a headache.

Only some large twin blades walk-behind mowers and some lawn tractor mowers are likely to have one only left-hand threaded blade bolt; the other bolt will be a regular right-hand thread.

How do you know which is which?

Simple, if the blade is designed to cut turning right (viewed from above), then it will be a right-hand thread; this is the most common type. To loosen a right-hand thread, you turn it to the left.

The same idea applies to twin-blade tractor mowers. However, a left-hand thread is common on some lawn tractor mowers.

So, if the blade cuts grass turning to the right, as before, it’s likely a regular right-hand thread (left to loosen). But it’s not uncommon for a tractor mower to have one of the blades turn to the left when cutting, and that usually means it’s a left-hand thread (check your owner manual) to loosen a left-hand thread, turn it to the right.

L/H – R/H Thread

A r/h thread loosens to the left. This is the most common type of thread. (counterclockwise)

A l/h threaded bolt loosens to the right. (clockwise)

Typical torque specs for blade bolts are anywhere from 35 ft. lbs. to 90 ft. lbs., you’ll need to check the spec of your mower, it’s important to get it right.

Most of the time blade bolts just get buttoned uptight and aren’t torqued to spec, and that’s OK, but you run the risk of bending the crankshaft if you hit a solid object. I advise using a torque wrench, it’s a lot cheaper than a new mower engine.

Torque wrenches are easy to use, they come in inch-pounds for smaller torque specs, but for mowers, you’ll need foot-pounds. A torque wrench from 30 to 100 foot-pounds is about right.

If you don’t have or can’t borrow one, check out this post on my 1/2 drive Teng Torque, it won’t break the bank, it covers 30 to 150 ft. lbs., it’s simple to use, calibrated from the factory, and has a flexible working range.

Measuring your Rotary Mower Blades

I get my torque wrenches calibrated every year but it gets a lot of use. If you set your torque wrench to zero after you use it and don’t throw it around, it should stay calibrated for years.

Damage – The bolt on the right has a rounded head, this kind of damage happens when a tool slips on a bolt head, or corrosion deforms it. Getting the bolt out presents a challenge.

A rounded bolt head is a real pain in jacksie. It usually happens when the bolt is old and corrosion has deformed it. Worn or damaged tools will give you the same result.

It can also happen if the wrong size tool is used. An American mower may use imperial size nuts and bolts, I know the more modern kit is metric and some mowers are a mix of both. If your mower is European or Asian it will be metric sizes.

The trouble is you can get an imperial wrench to almost fit a metric bolt, but it’s loose and will slip, which rounds the bolt head. Typical bolt sizes for mower blade bolts are Imperial 1/2″, 5/8″, 3/4″ and Metric sizes 13mm, 14mm, 15mm, 16mm, and 17mm.

Imperial or Metric, be sure your tools are a good fit.

Tools You’ll Need

Impact power tools are designed for this exact job. They cause a hammering action which helps reduce the bolt thread friction and breaks any corrosion loose. So if you have an air or battery impact tool, you going to feel like a superhero when that bolt just walks out.

Basic tools needed assuming you don’t have an impact tool: wire brush, wd40, ratchet sockets, selection of wrenches.

Other tools you’ll need if things don’t go exactly to plan: breaker bar, hammer chisel, butane torch, and if everything goes to crap, a Mig welder. In my workshop, I use an air impact tool, if you haven’t got one or can’t borrow I have other solutions for you.

rotary, mower, blade, bolts

But the tool I am least likely to be without is an impact tool, it just makes life really easy and saves so much time. The coolest thing about the latest generation impact tools is their mobility, cordless now packs the power of an air tool. Great for around the home and for flat wheel emergency, use it to run the jack-up and take the nuts off.

Although I still use air in the workshop, I bought a 20v Ingersoll Rand cordless for mobile repairs, I know they ain’t cheap but you won’t ever need to buy another.

If you do buy an impact tool, you’ll need to buy impact sockets too. Sure you can use regular sockets, but you run the risk of them shattering. Anyway, you’ll find all these tools on the “Small engine repair tools page”.

Tool Up – Most stuck bolts won’t need all these tools, but some do.

Removing The Bolt

Removing a stuck bolt involves trying different solutions until you ring the bell. In the first attempts, we’ll try the simple stuff and if that doesn’t move it, I have lots more ideas.

Before we start any work on our mower we need to make it safe. Pull the plug wire off and set it away from the plug. Turn your gas off if you have a gas tap, if you don’t know where your gas tap is check out “Gas tap location”.

WD40 is my favorite tool, it solves lots of problems, I also like a product called nut buster, it’s formulated for dissolving rust. Try spraying the bolt liberally above and below the blade, and allow it time to work into the threads.

Disable Mower – For safety, let’s remove the plug wire and turn off the gas.

Turn the mower over with the carburetor side facing up, stops gas leaking on the floor. (see tilting mower over)

Wire Brush to remove any rust. Wd40 Spray front and rear of the bolt and give it some time to soak in.

Impact Tool – By far the preferred way to remove a bolt. An Impact gun hammers the bolt as well as twists it, this loosens the corrosion between the threads.

An impact tool will remove the bolt in seconds and you won’t need to lock the blade. But if the bolt head is rounded, the impact tool is of no use. You’ll need a different solution.

Check out the Amazon link, some of these impact wrench surprised me.

Lock Blade – If you are not using an impact tool we’ll need to use a piece of timber to lock the blade against the body. Longer timber is better than shorter. Cut a length to suit.

Good Fit – Select a socket (6 points preferably) and check the fit. Turn the ratchet left to loosen. Using a breaker bar, or if you don’t have to improvise with your ratchet and some pipe.

Pushing down on the pipe will give you the extra power you need to break it loose. Just be sure the socket is a good fit, and it stays on the bolt head when you’re applying force.

Wrench Leverage – Turn the Wrench left to loosen. If you don’t have a ratchet and breaker bar, try 2 interlocked wrench’s for extra leverage, or use a hammer to shock the bolt.

If it still won’t budge, try tightening it slightly, this often helps, odd I know!

Striking – Try striking two hammers sharply (wear eye protection) while one is placed against the bolt head, this can help break loose any corrosion on the threads. If the head of the bolt is rounded, move on to the next solution.

Rounded Bolt – If your bolt head is rounded, try a vice grip. Get it as tight as you can, and try hitting it to the left sharply with a hammer.

Not all vice grips are the same, for this application you’ll need a flat jawed set. Check out this post on Vice-grips tools.

Chisel – This method is pretty effective, but you’ll need a new bolt, sharp metal working chisel, and a heavy hammer. With the chisel and hammer, take a sideways and downward aim at the bolt, we’re attempting to loosen it by turning it left. This will require good aim, so now’s a good time for those gloves.

Heat – Ordinarily I’ll tell you to get some heat on the bolt, the reason I haven’t introduced it earlier is that it comes with the risk of damaging the crankshaft nylon seal, which would cause the engine to leak oil.

The risk of this is fairly small, once you direct the flame and only use a small amount. We’re not going to redden the bolt, just going to heat it up.

Maybe 2 minutes with a butane torch directed at the bolt. You can now try heat with any combination of the above methods. Heat is very successful at helping move stuck bolts.

Welding – This method will obviously require a welder, when I get a really stubborn bolt with a rounded head, I take a new bolt and weld it to it. This gives me a not-so-pretty but clean bolt head to work with.

This solution has never failed me yet. You’ll need to replace the bolt. Blade bolts have a fine thread, they are a specialized bolt, getting one in the hardware store isn’t advisable.

Torque – Finally, you’ll have to move your timber to lock the blade in the other direction and torque your new bolt to spec.

Check out this post to see why it’s important to torque your blade bolt.

Related Questions

The spindle turns when removing the blades? The easiest way to prevent the blade from turning while loosening the blade bolt is to use a large block of wood to lock the blade against the mowing deck.

Lawnmower blade bolt direction? Turn the mower on its side, carburetor side up, turn the blade bolt to the left (anticlockwise) to loosen.

Hey, I’m John, and I’m a Red Seal Qualified Service Technician with over twenty-five years experience.

I’ve worked on all types of mechanical equipment, from cars to grass machinery, and this site is where I share fluff-free hacks, tips, and insider know-how.

And the best part. it’s free!


IHOF spare parts are non-genuine parts. All references to original brand descriptions and part numbers are made only for the sake of comparison. The unauthorized use of the drawings depicted, constitutes an infringement of copyright and will be prosecuted by us.

The trade mark has been placed in our illustrations with the sole aim of protecting our illustrations as part of our intellectual property.

Bolt for rotary mower blades. M12x1,75. 12.9

Part fitting for machine…

IHOF spare parts are non-genuine parts. All references to original brand descriptions and part numbers are made only for the sake of comparison. The unauthorized use of the drawings depicted, constitutes an infringement of copyright and will be prosecuted by us.

The trade mark has been placed in our illustrations with the sole aim of protecting our illustrations as part of our intellectual property.

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