4.1.1 – Fit a BrushDestructor Blade

On this page you will find out how to to fit a BrushDestructor blade to you brush cutter and some common problems found with the different brands of brush cutter that can complicate the mounting of the blade.


Models-17, 19, 20, 21 & 22

BrushDestructor Blades

Below is a quick video, showing you how to fit and remove the 25.4mm to 20mm step down ring, so you can fit this blade to brush cutters with 20mm arbors. To my knowledge, only the larger Stihl and Shindaiwa brush cutters have a 20mm arbor, but if you have a brush cutter other than one of the machine mentioned which has a 20mm arbor, please let me know. This will help me get a better idea of the number of machines that might require a step down ring.

There is no talking on this video, it is all pretty obvious. To make it easier cut a piece of wood as shown to support the blades while you hammer the adaptor ring in place, as it is a push fit.


 How to Fit a Model-17 Blade

Murphy’s Law says, that if you have never fitted a metal blade to there brush cutter before, one thing you are going to need is a reverse thread lock nut. This is because you will have either misplaced it (like I did), or because it was not supplied with your brush cutter, which is becoming more and more common these days. I have been asked on a few occasions, why I don’t supply these lock nuts. Unfortunately this is not practicable, as there are a number of different thread sizes used by the different manufacturers and for me to do so would add another cost to an already very expensive blade. Especially when most customers who purchase this blade, have already used a metal blade on their brush cutter and already have the blade mounting kit.
If you do not have a blade mounting kit, you only need to buy a reverse thread locknut from your brush cutter supplier, as the spring washer and nut guard are built in as part of the BrushDestructor blade. So don’t get talked into buying the whole kit.
Below are a number of videos showing how to fit a metal blade to a range of brush cutters and fitting the BrushDestructor blade is no different. If you do not find your brush cutter listed below, by the time you have watched all of these videos, you will have no problem fitting a BrushDestructor blade to you machine.
This first video, shows the fitting of a metal blade to a Honda Brush Cutter and the changing over from a grass to a metal blade guard. About a minute into the video you can see him bolting on the metal blade plastic guard and see the square metal bolting plate that holds the guard in place. If you move this square four holed bolting plate forward as far as possible and then use it as a template to drill four new homes in the plastic guard. You will then be able to bolt the guard on, with it moved back about 15mm and this will allow just enough clearance to fit the BrushDestructor blade.


Below is a video of the fitting of a metal blade to a Stihl brush cutter. Also if you take a close look at the guard, you can see that it is very similar to the Honda guard. The bolt holes are also a perfect match, so this guard will bolt straight onto a Honda brush cutter and because it is bigger will give you a lot more blade clearance as you can see in the second photo of two brush cutters upside down above.


This video below shows the fitting of a metal blade to a Husqvarna brush cutter.


This is another video fitting blade to a Stihl brush cutter. For Husqvarna owners you can buy the metal nut guard that you can see below from a Stihl or Honda supplier and fit it to your machine to protect the nut and threaded end to the shaft.


This video shows fitting metal blade and guard to an Echo Brush cutter.


Fitting to a Ryobi brush cutter


Fitting a blade to the typical cheap Chinese brush cutter found on eBay.


The second half of this video shows the fitting of a metal blade and plastic guard to another typical Chinese brush cutter.

One final thing, on brush cutter where the guard has been designed for use with a line head, you need to remove the line length cutter blade and store it away safely.

You should do this even if the flail blade does not touch the steel cutter, as you will end up cutting heavier material than grass and the larger and heavier debris will break it off. So that you end up losing the cutting blade and chances are breaking its mounting points as well.

Model-16 Blades and earlier
The biggest problem with earlier model blades of larger diameter, was the blade tip hitting the guard.
This was especially a problem with my favourite brush cutter the Honda when the plastic guard meant for a metal blade was installed. This is not longer an issue with the Model-17 blade as it is smaller in overall diameter the previous model blades.
If you should end up acquiring one of the earlier BrushDestructor blades and have a Honda brush cutter, it is easy to modify so as to move it back, to make it suitable for use with a BrushDestructor blade. See the notes above the video below on fitting a metal blade to a Honda brush cutter.
The other option is to buy a Stihl metal blade plastic guard which has exactly the same mounting holes, but because it is larger it gives much more clearance above and to the back of the blade. Even though this guard is no stronger than the Honda guard, the Stihl guard lasts longer because of the increased clearance.
Below you can see the damage to the black Honda guard caused by branches getting dragged between the blade and guard which eventually wears a hole through the back of the guard.

The problem for owners of Husqvarna brush cutters, is the massive nut guard that comes standard with their brush cutters as you can see below. In the past they use to come with the driven washer and nut guard made as one piece, so the you didn’t have to use the large plastic nut guard which you see in the second picture below.
Unfortunately, now days they supply the more traditional driven disc spring washer and locknut and because you cannot fit the large plastic nut guard you cannot use this part with a BrushDestructor blade and that leaves the end of the drive shaft thread exposed to damage.

Fortunately, this is no longer an issue, as the new Model-17 blade has a nut guard built in as part of the blade and so any other manufacturers supplier nut guards are no longer required.