2.3.3 – Model-14 BrushDestructor Blades

BD Model-14 2 & 2 Blades Models (580x204)

The model-14 blade was released in two models, the 3 bladed model called the BrushCutter-Blade and the 2 bladed model called the WeedEater-Blade. The Flail-Blades now had a serrated front edge for mulching and a single easy sharpen tooth. These models were more aimed at the commercial operators and those with larger properties that require a lot of maintenance. This BrushDestructor-Blades can easily clears everything from grass up to 100mm diameter hardwood gum saplings.

Below are all the improvements found on the Model-14 blade compared to the older Model-11 Blade.

BrushDestructor Model-14 and Model-11 Blades (580x192)

Top and Bottom Hubs

The shape of the hubs has changed and the distance between the hubs has been reduced to act as a guide for the flail blades. When the flail-blades hit a non-giving object or is driven very hard; the flail-blades get, either flicked forward or backwards at very high velocity. Also what happens is the blade gets bent, which is not a problem for this steel, but a bent blade would start to cut into the hub with each impact. In all the previous models this was dealt with by adding spacer washers between the top and bottom hubs to allow for this flexing which of cause added weight and cost to the BrushDestructor-Blades.

One of the unexpected benefits of the reduced distance of 2.2mm between the top and bottom hubs is that the plant matter that gets wedged there, it stays there. When there was an 8mm spacing, the plant matter would sometimes clear itself, resulting in an unbalanced blade that would vibrate a bit until new plant matter got wedged in.

Bolts and Bushes

The bush has been replaces with a hardened spring washer; this is mainly as a cost savings measure so we no longer need a custom made bush, but use an off the shelf hardened spring washer. The other reason for using a 2.2mm high washer is that going from 8mm to 2mm space between the top and bottom hubs considerably added to the shear strength of the anti-fouling-blades that also served as impact stops for the flail-blades.

The button head stainless steel bolts have been replaced with high tensile socket head bolts, which are much stronger and can be torqued up much tighter. This is to prevent the bush washers from rotating on the bolt, causing considerable wear to the bolt, instead of the blade rotating on the bush as it is supposed to. (Refer left Photo of damage to bolt) The button head bolts uses a much smaller Allen key than the socket head bolt which is the main reason why customers could not torque up the bolts tight enough. The much larger Allen key used in the socket head makes it much easier to torque up to prevent washer rotation. (Refer right photo of bolt heads)

BrushDestructor Fastening Bolts


The serrated teeth on the top edge of the anti-fouling-blades have been made much more aggressive so they are better at shredding tough long stringy grass and vines that should wrap around the gear head. The angle of these serrated teeth have been trialled to ensure they do not clog up and prevent them from doing their job of clearing the gear head.

The second main purpose of the anti-fouling-blades, is to act as impact stops for the Flail-Blades, but there has been a couple of failures of the anti-fouling-blades.

Firstly, by those with very high powered WhipperSnipper’s, WeedEater’s or BrushCutter’s, who have the power to keep pushing into the job harder as the teeth on the Flail-Blade loose their edge. This then starts flicking the flail-blades backwards harder against the stops, keep this up long enough and the flail-blades will eventually punch their way through the from the rear of the anti-fouling blades.

Secondly, by those that unknowingly cut in both directions  with their brush cutters, when you should only be cutting with the right to left stroke. If you are cutting on the back stroke (left to right) you will cause a lot of shock waves to your brush cutter, this breaks everything from nylon lines right up to this BrushDestructor Blade. I will explain what happens here and why in depth on a page of its own in the near future, but the result is in this case that the flail-blade is flicked forward at very high velocity and with enough power to quickly shear its way right through the anti-fouling blades as shown in the picture below.

Damage to Anti-Fouling-Blades

To prevent this, those Anti-Fouling-Blades that act as impact stops have been doubled up to make them stronger and hopefully prevent them from failing.

The location of the anti-fouling-blades has been changed to prevent one flail-blade hitting the other and damaging or knocking off the tips of the teeth. The photos below show how the Flail-Blades used to hit one another and damaging each other. The new Flail-Blade design and location of Anti-Fouling-Blades prevents this from happening.

New Flail-Blade Clearance


The main improvement of this redesign is the change to one cutting tooth, from the four teeth on the previous model. This gives it a slight improvement in cutting and a slight reduction in the power required to drive it. Especially when the four teeth on the previous model lost their edge, causing much more drag and load on the Brush cutter.

This single tooth is stronger with much more metal behind the cutting edge, this plus the impact shoulder in front of the tooth make it less prone to major chipping, so if it should hit a really hard stone causing it to chip, the chip should be smaller and easier to grind out. The trailing edge, which is parallel to the cutting edge, makes it easier to maintain the correct cutting angle as you keep grinding it back the tooth to keep it sharp.

The other advantage of the single tooth per blade is the much reduced time it takes the keep only three teeth sharp, so operators are more likely to keep it sharp. I recommend that you touch up the edge of the tooth, every time you refuel your brush cutter. The little time this now takes, more than pays for itself in area cleared.

The serrated front edge to the new flail-blades, creates high pressure impact points allowing it to more easily shred tough stringy grass and weeds without it sticking to the blade.

New and Old Flail Blade

The image above gives a comparison between the old Extra-Heavy-Duty-Blade and the new WhipperSnipper-Blade, WeedEater-Blade and the BrushCutter-Blade. One thing you will notice is that the blades are much wider; this is to reduce the bending of the blades and allow it to slide in between the top and bottom hubs. The other important thing about the new WeedEater and BrushCutter-Blades is that this extra width allows you can keep sharpening them for a lot longer with much less reduction in overall diameter, thereby getting maximum value from each set of Flail-Blades.

BrushDestructor Flail-Blade as it wares down

The image above shows how I anticipate it wearing down as it is resharpened over time. This drawing will be replace with photos as I sharpen and ware one down. Once the brush cutter-blade gets much past that shown on the right, I recommend that it is replaced for new blades.

This video show to quickly resharpen these new blades

Top and Bottom Hubs

The main difference of this model is the increase in overall Diameter of 30mm. This gives a higher tip speed, combined with the heavier blades gives much more punch and cutting power. The down side is that this small increase in diameter required a lot more power to drive it.


With the New BrushCutter model, four extra Anti-Fouling-Blades have been added and again this improvement provides multiple benefits, in this case three. This does come at a cost though as the extra drag sucks up more power from the machine and one of the reasons for recommending it is more suited for brush cutters over 35cc. It does still work well with Brush cutters under 35cc, I have done hundreds of hours of testing with my old Honda 22cc brush cutter, you just need to keep the teeth really sharp and not push it as hard and it will still do a reasonable job.

The first is the improvement of clearing plant matter that has wrapped around the gear head that could stall a WhipperSnipper, WeedEater, or BrushCutter engine. This is due to the extra anti-fouling-blades, positioned in an outward spiral which creates a much stronger turbine effect improving cutting and spitting out of entangles plant matter.

The second is to reduce the impact load on the anti-fouling-blades caused by the higher powered machines. This is achieved by moving the impact point further away from the pivot point of the blade, (refer image below) the greater this distance, the less the impact load on the anti-fouling-blade. 

Flail-Blade Stops

The third is the prevention of the flail-blades from hitting one another and damaging the sharp teeth. This ensures the brush cutter-blade cuts more efficiently, and for much longer than the previous model.

All the many improvements that have been incorporated into these new BrushDestructor-Blades, are a result of feedback from you the customer. It is the feedback where there has been issues or failures that have driven me to solve these problems and continue to improve this product. Commercial operators have been my biggest source of feedback, they are the ones that use a brush cutter all day, everyday and the one that benefit the most from a better product. I always keep thinking that this new model will be as good as it gets, but I now know that there will always be improvements, the more people that use these BrushDestructor-blades, the more the correspondence I get back from you, the better the product will become.

Model-14 Spare Parts

I have limited spare parts for this model, please contact me for more details.