Are Lawn Mower Blades Reverse Thread

Are Lawn Mower Blades Reverse Thread

Removing the lawnmower blades is an integral part of any mowing vehicle maintenance. This involves unfastening a nut that secures the blades in place.

But are lawn mower blades reverse thread? How you answer this question will determine how you unfasten the mower blades to clean, sharpen, or replace them.

You may also want to remove the mower blades from their place on the drive train to service the deck.

This article helps answer the question as it applies to various lawn mower brands. It also provides useful tips on how to remove the blades safely.

Are Lawn Mower Blades Reverse Thread?

No, the lawn mower blades are not reverse thread, but some nuts are reverse. In fact, most screws and bolts are threaded in a standard right-hand fashion, but there are a few screws out there that have a left-handed thread. So next time you decide to work on your lawn mower, it might be a good idea to check the thread first before you start tightening anything up!

What is a Reverse Thread?

Reverse threading refers to a method of fastening that involves using bolts that screw in an anticlockwise direction.

Such bolts are reverse threaded, so you tighten them by screwing them counterclockwise and unfasten them clockwise.

A reverse-threaded retaining bolt has threads that spiral around the shaft anticlockwise. So when you talk about a mower blade’s threading, you refer to the bolt that holds it in place, not the blade itself.

This bolt connects the lawnmower blade to the drive train. Notice that the drive train is responsible for spinning the blade, enabling it to cut the grass.

Are Lawn Mower Blades Reverse Thread

Depending on the manufacturer, some lawnmower blades are reverse thread while others are not.

Almost as many lawn mower brands are threaded clockwise as anticlockwise, even though some believe most lawnmowers are reverse-threaded.

Whether the blade’s retaining bolt is reverse threaded or not, the blade always moves in the opposite direction when cutting to avoid loosening the retaining bolt.

This means that if the bolt is fastened counterclockwise, the mower blade will move clockwise when operating.

On the other hand, if the bolt is threaded in the standard fashion (clockwise), the blade’s direction of movement will be opposite (counterclockwise) when mowing.

Why is the Direction of Threading Important?

Knowledge of the direction of threading comes in handy when removing the mower blade.

You want to know the direction of the threading to determine which direction to turn the bolt securing the blade to the drive train.

You want to avoid struggling with a wrench for minutes, only to realize you have been twisting the bolt in the wrong direction, tightening it further instead of undoing it to come off the threaded shaft.

While many lawnmowers have a reverse thread, others don’t. So you need to have a way to tell whether your specific mower has a reverse threaded bolt or not.

Most importantly, threading is designed to help tighten the bolt further with every mower blade rotation. This is essential as it helps prevent the blade from falling off accidentally while mowing.

With the right threading, the lawnmower blade will remain securely attached to the drive train.

For this to work successfully, the center of the mower blade spins opposite the unit’s cutting rotation.

How Do You Know If Your Lawnmower Blade is Reverse Threaded?

The best way to know if the blade on your lawnmower is reverse-threaded is to read through your operator’s manual.

Since some manufacturers use the standard threading fashion while others go for the reverse threading system, it may be challenging to determine the direction of the bolt threads without confirmation.

Alternatively, you can determine the direction of threading by observing which way the blade spins. The threading will be opposite the direction of the mower blade’s rotation.

To use this strategy, you will have to tip the lawnmower on its side with the air filter side of the engine facing upward.

This will allow you to access the blade underneath your walk-behind mowing deck. From there, you should be able to observe the blade, see the sharp side and determine its direction of rotation.

Finally, you can use the position of your mower’s discharge chute to determine its threading direction. Mowers with right-hand (non-reverse) threaded systems have this chute on the right.

Lawn Mower Blade Bolt Direction

The direction of the mower blade bolt is crucial when removing the blade to change it, sharpen it or clean it.

Whatever the reason for removing the blade, you must unfasten the bolt attaching it to the mower’s engine.

For this reason, you will need to know the blade’s retaining bolt direction of threading to unscrew it correctly.

Are John Deere Mower Blades Reverse thread?

No. The retaining bolt attaching the blade to a John Deere lawn mower drive train is threaded normally.

This means you fasten this bolt by turning it clockwise, as with any standard bolt. When you turn this bolt counterclockwise, you loosen it, eventually getting it off the threaded shaft.

Are Cub Cadet Mower Blades threaded in reverse?

Not really. The bolt attaching the blade on a Cub Cadet lawn mower to its drive train is threaded clockwise. So you need to turn it to the right to tighten it and to the left to loosen it and remove it from its place beneath the mower deck.

Cub Cadet has this information on their website, explaining that their mower blades have a right-hand (normal) threading system. 

The threads on Cub Cadet Mower bolts are typically 5/8 inches, and you must tighten them a toque of between 70 and 90 foot-pounds.

Are Craftsman Mower Blades Reverse threaded?

Absolutely. Craftsman is among the known lawn mower brands using reverse threaded bolts to hold their blades in place under the mowing deck.

Turning the bolt to the left (anticlockwise) tightens it, while turning it to the right (clockwise) untightens or loosens it.

Craftsman specifies the torque value recommended for their bolts in the operator’s manual.

You should check this information before embarking on tightening or unscrewing the Craftsman lawn mower blades nut from underneath the deck.

Are Toro Mower Blades Threaded in reverse?

No. Like honda lawn mower blades, Toro lawn mowers have blades held in place by blades with normal threading.

Fastening the retaining bolt on a Toro lawnmower, therefore, requires turning the nut to the right. On the other hand, turning the bolt to the left will unfasten or loosen it.

Some experts recommend applying a drop of penetrating oil to these bolts when they jam themselves in place, refusing to come off.

This is because some users have argued that the lawnmower blade nuts on Toro mowers can be extremely difficult to untighten.

Are Troy Bilt Lawn Mower Blades Reverse thread?

No, the Troy Bilt Lawn Mower blade is not reverse threaded on its retaining bolt. Instead, the shaft has normal threading, meaning that you tighten it by screwing it to the right and untighten it by turning it counterclockwise.

According to the manufacturer, this bolt requires about 70-90 foot-pounds of torque to tighten it securely.

Are Gravely mower blades reverse threaded?

No, the bolt attaching the blade to a Gravely lawn mower drive train is right-hand threaded. This means the threads on this bolt spiral normally and not in reverse.

So, when undoing the bolt, you will need to rotate it counterclockwise. Likewise, when tightening the bolt, rotate it clockwise.

Often, when replacing an old or damaged blade in this mower, you will want to start with a free hand rotation to get the bolt someway in before switching to a wrench to tighten it to the recommended torque.

Are bush hog blade bolts reverse thread?

Yes. Bush Hog blade bolts are reverse-threaded. As such, they tighten by rotating to the left or counterclockwise. To unfasten these bolts, you need to rotate them to the right or clockwise direction.

The information regarding the amount of torque to apply for these bolts to tighten them securely should be available in your owner’s manual.

How to Safely Remove Lawn Mower Blades

Lawnmower blades are sharp, with some rugged on the opposite ends. This means you must be careful when unfastening them to avoid injuries.

You also don’t want to damage the blade, so ensure you follow the correct procedure when removing your mower’s blade.

Most lawn mower owners can replace or service their mower blades using simple tools. Ideally, you will need the following:

  • Safety goggles for eye protection
  • A pair of thick, protective hand gloves – preferably leather
  • A block of wood
  • A plastic bag
  • A ratchet wrench with the right-size socket
  • Putty knife (optional)
  • Torque wrench (for tightening the blade bolt)

Once you have all the supplies, follow the following procedure to complete the job.

Step 1. Disconnect the spark plug

Start by removing the spark plug wire from the spark plug and tuck it safely away. You don’t want the mower to suddenly start while you service it and risk getting chopped by the spinning blade.

If the cutting tool is cordless, you should disconnect it from its power supply by removing the battery pack altogether.

This precautionary step goes a long way in preventing accidents related to unintended start-ups.

Step 2. Protect the gas from leaking

Use the plastic bag to cover the gas tank and secure it tightly in place using the gas cap. This will help prevent the fuel from leaving when you tip the mower on its side.

Some guides recommend draining the gas tank, but that is not necessary when you can simply seal the gas tank to keep the gas from leaking during the exercise.

Step 3. Tip the mower on its side and secure the mower blade

Once the mower is disconnected from power and the gas is secure, tip it on its side with the air filter side of the engine facing up.

Next, wedge a block of wood between the blade and the mower deck to prevent the blade from moving while loosening the bolt. This step will also allow you to use both hands to untighten the bolt.

It is also essential for blade bolts that are too tight or rusted. Such will require more force to loosen.

Step 4. Note the blade orientation

Most mower blades come with a stamp indicating the grass side or the side to be up.

However, consider noting the blade position and orientation before removing it to avoid any confusion when returning it or installing a new one.

You want to note which blade side faces up and which side faces down to prevent mistakes.

Often, the side facing up will have wings, while the side facing downward (grass side) will be slightly lower toward the ground.  

Step 5. Loosen the blade nut and clean the underside of the mower

Once you have secured the blade with a block of wood, wear a pair of leather gloves, and use both hands to loosen the bolt. You can hold the blade with one hand while you use the wrench to rotate the bolt.

The underside of the mower deck may have glass buildup. Use a putty knife to remove the debris before installing the new blade.

Step 6. Install the replacement blade

Once the underside of the deck is clean, hold the sharpened blade or the new one against the mower blade adapter with one hand and screw in the bolt with the other.

Once the bolt is in place, tighten it with the torque wrench, observing the specific torque values the manufacturer recommends.

FAQs

Are lawn mower blade bolts reverse thread?

Only some manufacturers choose reverse threads for their mower blade bolts. So not all lawnmower blades have reverse-threaded bolts.

Are mower blades clockwise or counterclockwise?

Most lawnmower blades are designed to rotate clockwise when viewed from above, so they have a sharp cutting edge on the right side. You can always check the chute position to determine which direction the mower blade rotates. A right-side discharge chute indicated a blade turning clockwise and vice versa.

What is the right Lawn mower blade removal direction?

The right lawn mower blade removal direction can be clockwise or anticlockwise, depending on the threading on the blade retaining bolt. Always check the owner’s manual for this information as it applies to your mower.

How to tell if a bolt is a reverse thread

A reverse-threaded bolt has a counterclockwise thread, and you can tell if yours is this type by looking up the information in your owner’s manual.

Final Thoughts

Most lawnmower blade nuts are threaded normally, but not all of them.

So you may not be able to tell whether yours is reverse threaded or not until you check the information on the user manual or directly observe the blade direction.

Alternatively, check this guide for information regarding the threading for your specific mower. We hope the information was helpful.

Let us know your thoughts in the comments.