Mower blades hitting each other can be a major annoyance, especially when you’re trying to tackle your lawn-care tasks. It is not only loud and disruptive but also causes significant damage to your mower and results in costly repairs.

You can usually avoid the problem by knowing why mower blades are hitting each other. A number of factors, such as blades out of place or incorrectly adjusted mower deck height, can cause the blades to hit one another during operation.

Bent and/or worn cutting blades can also make it harder for them to move freely, resulting in them colliding with one another instead. Identifying these issues and preventing them will help you keep your mower running smoothly and efficiently for a long time.

Why Are Mower Blades Hitting Each Other: Hidden Causes With Preventions

What Causes Mower Blades to Hit Each Other - Common and Hidden Causes and Preventions

1. Poorly Balanced Blades (Blades are out of Place):

When mower blades are not evenly balanced, they can hit each other as the lawn mower rotates them. This problem is often caused by a lack of maintenance.

If the blades have not been regularly sharpened and properly balanced, they can become unbalanced over time. Additionally, if the blade bolts are missing, it can cause the blades to be out of place and cause them to strike each other when in motion.

Prevention: Maintain an even balance between blades to prevent poorly balanced blades.

2. Incorrectly Adjusted Mower Deck Height:

If the deck of a lawnmower is too high off the ground, the blades can come close enough to each other that they will hit while the mower is in use. A deck height that is set too low can also cause problems. The grass may get caught between the blades and hit each other.

Prevention: Operators need to ensure that their mowers are always adjusted correctly for their given terrain.

3. Bent or Worn Cutting Blades:

Cutting blades that are bent or worn can easily make contact with each other during operation due to their diminished shape and size. Dull blades may move independently from one another because they lack the proper cutting edge needed to create a uniform spin around their axis point.

Prevention: You should replace them as soon as possible after noticing any signs of wear and tear on their edges.

4. Rotational Issues with the Engine or Motor:

The engine or motor of a lawnmower determines how quickly its cutting blades rotate. If there’s a rotational issue, then it could cause the blades to hit each other while in motion.

This problem could be due to a faulty air filter or spark plug, bad gasoline, clogged fuel lines, an old oil filter, or even something as simple as low battery power in electric-powered mowers.

Prevention: You must always keep up with basic maintenance tasks like changing the oil and air filters regularly to avoid rotational issues with their engines or motors that could lead to blade-on-blade contact during use.

5. Clogged Undercarriage and Grass Buildup:

Clogged Undercarriage and Grass Buildup

One of the most common causes of mower blades hitting each other is a clogged undercarriage or buildup of grass underneath the mower deck. This can easily occur due to long grass accumulating between the blades, preventing them from spinning freely and efficiently.

It can lead to an uneven distribution of power when it comes time to cut the grass, resulting in an uneven cutting pattern and eventually leading to one blade hitting another.

Prevention: To mitigate this issue, it is essential to regularly check the underside of your mower for any debris buildup or clogging and ensure all blades are properly aligned.

6. Loose Fasteners and Hardware Components:

Due to vibration or excessive movement of these parts, loose fasteners or components can cause your mower blades to hit each other during operation.

The fasteners, if they are not regularly checked, may become loose, resulting in the blades not being able to maintain their alignment as well as the blades ultimately making contact with one another while cutting the grass. In this case, the blades can break from the lawn mower or the edge of the mower.

Prevention: Ensure that all screws, bolts, and nuts used on your mower are tight at all times. This will help keep your mower running smoothly with its blades properly aligned.

7. Defective Pulley System or Belts Tensioning Mechanism:

Another common cause of mower blades hitting each other is having a defective pulley system or belt tensioning mechanism on your machine. Wear and tear with these parts can prevent them from keeping up with the torque required for proper blade alignment, resulting in them hitting one another during operation.

Prevention: Regularly inspect these components for signs of wear and tear and replace any defective parts as soon as possible to ensure optimal performance from your lawn mower’s blade system.

How To Fix Mower Blades Hitting Each Other?

There are 2 methods to repair mower blades hitting each other: 1) Turning the blade over by hand where it is banging and 2) Installing new blades.

Method 1: Taking the Blade and Turning it Over by Hand

Taking the Blade and Turning it Over by Hand

I. Lift the Deck:

To lift the deck of a mower, you need to first make sure that it is turned off and unplugged from any electrical source. Use a jack or another tool that can support the weight of the mower so that you can safely get the deck up onto its side.

Be aware of where your hands and fingers are at all times, as there may be sharp blades or other parts that could cause injury if touched improperly.

II. Cleaning off Grass and Gunk from the Blades:

Clean off any grass, particles, and gunk from the blades of your mower in order to ensure they are running properly without obstruction. Use an air compressor to blow away any debris, then use a brush and some soap and water to scrub down each blade thoroughly until they are visibly clean.

III. Turning it by Hand to Spot Where it is Banging:

Place the mower back onto its side, then turn it over by hand so you can spot where two blades are hitting against each other when they spin around together on their spindle shafts. It is important here to remember which two blades were hitting so that you can properly adjust them individually in step two below.

IV. Adjusting Pitch of Blades:

The pitch of the blades needs to be re-adjusted in order for them not to hit one another when turning around on their spindle shafts. By doing this, we can identify which ones were crashing into each other.

Using a wrench or an Allen key, carefully loosen each screw from one blade at a time until you have loosened them both enough for adjustment. In order to space out the angles between them equally while spinning around together on their shafts, you need to move either blade outward or inward.

After spinning them around one more time by hand, tighten them again with your wrench/Allen key tool.

VI. Ensuring Equal Distance Between Blades on Spindle Shafts:

After both blades have been repositioned according to pitch adjustments, make sure they spin with an equal distance once more around the spindle shafts. Use an Allen key/wrench or your hand to make sure it’s done correctly.

In this way, the blades will move smoothly during use without impactful bumps caused by a misalignment of the spindle shafts.

Method 2: Installing New Blades (If Necessary)

Installing New Blades

1. Buying New Blades with the Correct Length, Width, and Thickness

Buy blades based on the mower deck size and other factors such as blade length, width, and thickness. The wrong size or model of the blade could result in blades that do not fit correctly on the mower deck and cause them to rub against one another.

For proper blade replacement when purchasing a new lawn mower blade, it is best to measure the mower deck before making a purchase.

2. Removing Old Blades from Mower Deck

The first step when replacing old blades on a mower deck is to remove them from their current position safely and securely. To do this, turn off the engine of your mower and disconnect any cables attached to it, such as those running electricity or fuel lines.

Once completed, use a wrench or other suitable tool to loosen any nuts or bolts holding the old blades in place. Carefully lift out each blade so they can be discarded or recycled accordingly.

3. Attaching New Blades to Mower Deck

Once you have removed all of the old blades from your mower’s deck, it is time to attach your new blades in their place. Align each new blade with its corresponding mounting hole on the mower’s deck so they are properly aligned when installed.

Using strong bolts, carefully secure each blade into place, ensuring that they do not overlap one another at all (as this will prevent them from hitting each other).

Tighten all bolts using a wrench until firmly secure in order for them to remain properly fastened during the operation of your machine. To finish, ensure no sharp edges are touching each other, as this could result in damage over time due to friction caused by extended use.

Should Lawn Mower Blades be Straight?

Should Lawn Mower Blades be Straight

Lawn mower blades should be straight in order to ensure the best performance and to prevent any damage from occurring to the engine and body. If a blade has become bent, this can cause noticeable signs such as stalling of the mower, uneven cutting of the grass, strange grinding noises, and bumpy handling during use.

To avoid any potential damage or safety issues, replacing a bent blade is recommended rather than attempting to straighten it by hand.

Should Sower Blades be Sharp to the Touch?

Mower blades should be sufficiently sharp in order for them to effectively cut through the grass without causing too much strain on the engine. Although they don’t need to be razor sharp, they should still be sharp enough to achieve optimal results quickly and efficiently. When you touch the blade directly, you may get cut if it is overly sharp.

What is the Ideal Pitch of a Mower Deck?

The optimal pitch of a mower deck should be between 1/8-inch (0.125 inch) and 1/2-inch (0.5 inch), meaning that the height of the deck rear should be higher than the height of the deck front.

A rotary mower’s wheels should be set to the same height, while a reel or flail mower’s owner’s manual will provide guidance on deck height. Any mower must maintain an equal distance from the ground on all sides, and the blade must circle at the same distance from the ground.

What is the Most Common Angle for a Mower Blade?

Mower blades usually have an angle of 30-35 degrees. This specific angle should be maintained when sharpening the blades, as it is what the blades come with from the factory.

Keeping this angle will help to ensure that the lawn mower blades are able to cut grass effectively and efficiently. Maintaining this angle over time can help to protect against any potential damage to the grass or turf caused by an incorrect blade angle.

Cut Grass Continuously Without Noticing The Mower Blades Hitting Each Other

Cut Grass Continuously Without Noticing The Mower Blades Hitting Each Other

Mower blades hitting each other is an all-too-common problem that can disrupt your lawn care routine and result in costly repairs. By regularly adjusting the mower deck height properly, you can avoid such issues and ensure that the mulching blades do not hit each other during operation.

Sharpening your mower blades regularly will prevent them from becoming bent or worn prematurely, which could lead to them clashing while in motion. Taking these precautions now can save you money, time, and peace of mind down the line.