A New Class Of
Brush Clearing Machine
This new machine will not be called a trimmer, a weed eater, a weed wacker or brushcutter, it will be the first of a new class, a BrushDestructor class, designed to complement the BrushDestructor Blade, for heavy duty land clearing, weed control & fire hazard reduction.
This machine is designed to be powered by the Honda GX35 belt driven overhead cam 4 stroke engine, but will be sold without the engine. This will allow those that already have a Honda brush cutter, to bolt on their engine, or to allow those in different countries, to go to their local Honda dealer to get a new compliant engine for their county to bolted on. The will allow them to have the Honda engine warrantee in their country.
Below is the first prototype built up of parts from different manufacturers and a custom made longer shaft. It may not look that different from any other brush cutter, but what this machine has cleared will blow your mind.
This is the custom made machine that you can see in the video above; it is powered by a 35cc Honda GX35 4 stroke engine, it has an extra long heavy duty shaft for reach and balance, a loop handle from a back pack brush cutter to give a wider swing and a Stihl heavy duty gear head and guard.
It will be the only brush cutter with a guide face to the front edge of the guard to stop the branch bouncing around, so that you can cut through that hard springy branch as if you were using a skill saw.
I get lots of emails from people, wondering when the new machine will be on the market, unfortunately development and testing of the Model-17 blade has taken precedence. Plus, having to do an increasing amount of assembly, wrapping, mailing and correspondence, has left precious little time for prototyping and testing. Also the very high tooling cost for many of the parts, has also slowed down development.
So I am going to start by making individual parts to upgrade the 35cc Honda brush cutter. Each upgrade will be designed to make the standard 35cc Honda brush cutter more suited for heavy duty clearing and fire hazard reduction. All of these parts will be available individually to start with and eventually as a complete unit, once all the parts have been developed and in production.
Although I am working on all parts, the planned order of upgrades I will be releasing is;
Extra Long Low Vibration Shaft – Fuel Tank Mods – Heavy Duty Guard – Ball Swivel Hitch – Loop Handle – Trigger Control Handle, – Gear Head – Clutch Housing.
All of these parts will be able to be available individually as they come on line, or eventually as complete unit but without the engine.
Extra Long Shaft
I will be working on the shaft first, because one of the biggest issues with brush cutters, is that one size does not fit all and the standard shaft length in my opinion, is really only good for someone that is less than 1.5m (5 feet) tall. I have had much feedback from customers that using their brush cutter for long periods causes serious back issues for many tall people, myself included. Refer to this page on Back Injuries on the Q & A Page
The other benefit of a longer shaft, added safety for the operator, as it will put the spinning metal blade further out of your reach, should you slip or stumble, plus you will be able to clear a greater area with its much wider sweep.
You will have to trust me on this, but once you have used a brush cutter with a longer shaft, you will wonder how you ever managed with a short shaft and you will never want to go back to a short shaft. I know this, because I find I have to force myself too used one of the review brush cutters with the standard length shaft, to even do a review of them.
The plan is to offer two different shafts lengths, 1800mm and 2000mm long to suit the different heights of brush cutter users. However this will not just be a longer shaft, it will also be designed to minimise vibration as well. The problem is, making a longer shaft, creates a lot of other issues. Just imagine a longer piano string, vibration and resonance all change for the worse.
Although the shaft should not produce any vibration in itself, it is the conductor of vibration coming from the engine and gear head and behaves very much like a guitar or piano string. With all of this vibration ending up going through the handles to your hands. Hopefully with a combination of different materials and clever design, I can considerably change the shafts resonant frequency, so that the vibration transferred to the hands is reduced.
Below is a really good video, that explains visually, the resonance in a pipe or tube. It is by Steve Mould and he has a way of explaining physic, that for everyone anyone can understand. I also recommend that you check out some of his other videos. This video only shows a vibration source at one end, just imagine how complicated the rogue frequencies are when you have a second source of vibration at the other end of the shaft, as in a brush cutter.
This moving image below, which is a short clip from the video below it, shows how resonance can produce rogue waves in a 28mm diameter x 2mm wall aircraft grade aluminium tube. These rogue waves can intensify to the magnitude that it can easily flex this very hard tube, to the point that it becomes easily visible to the eye and of cause with a brush cutter it is your hands that end up absorbing this.
I have bee looking a two different materials for the shaft;
The first option, is carbon fibre, which is very stiff, light and very expensive. But it is also cheaper to produce and bring to market, as there is no tooling costs and production runs can be small. I now have a first small run of 20, 1800mm long shafts ready to go. The weight of this 1800mm long carbon fibre shaft is only slightly heavier (1.3kg), than the standard 1500mm long Honda shaft, so there is minimal weight penalty for the longer shaft.
The final sell price for carbon fibre shafts, will be AU$250.00 but I have my doubts that people will pay this cost, for the benefits that a long shaft offers. So I will sell this first run at AU$199.00 to see if people are prepared to pay this amount.
The second option, is aerospace grade 7570 aluminium, which may be even stiffer than carbon fibre, a lot heavier and cheap. But it is also way more expensive to bring to market, as there is no suitable size tube on the market, so this will involve the cost of a custom extrusion die and a minimum run of one tonne of extruded aluminium, which is a large outlay. The weight of this shaft would be 0.5kg heavier than the carbon fibre shaft at (1.8kg) but I think the final sell price would be just under the AU$100.00 mark.
Whether this second option gets off the ground, will be based on feedback from customers who buy the first run of carbon fibre shaft and their thoughts on price verses weight.
Hopefully this is something that Honda will fix, but the GX35 fuel tank has a problem, at least with some engines in some countries.
The first is not being able to run the engine on its side, if the tank is less than half full. From my experience, I can state there is nothing more frustrating than the engine starving of fuel every time you turn the brush cutter on its side when the tank is less than half full.
The second is that, some models have a a fuel cap without a restraining cord, which means it can easily be lost. I should know, because I have lost a cap and in the process covered myself in petrol.
I have heard that Honda makes different engines to be compliant with regulations in different countries and had assumed that this was mostly related to pollution control. I had not expected that the fuel tank would be different. Below is a parts drawing I found of the Honda GX35 fuel tank, and it indeed shows that the fuel cap should have a retaining cord and that there are two lengths of fuel feeder hose. The longer hose, I presume, should be for the loop handle brush cutter. Yet for the Australian model, the fuel tank has no cap retainer and it only comes with a short fuel feeder hose.
These short comings might be OK with a bicycle handle brush cutter that is difficult to turn on its side, but definitely not with a loop handle brush cutter. Hopefully someone at Honda will read this and address this problem, so I don’t have to feel embarrassed about recommending the Honda loop handle brush cutters.
Heavy Duty Guard
That will be designed to fit the standard Honda gear head (as shown on the three images below) and the BrushDestructor gear head. Which will be designed to have the exact same mounting layout as the Honda Gearhead.
Below is the first prototype 3D printed guard, the second prototype will be made to fit the Honda Gearhead. I imagine though, that if it is anything like the blade, it will take a few more prototypes, before I have a production ready guard for sale.
This high strength guard will be designed to withstand any punishment that the BrushDestructor blade can throw at it.
The exterior shape of the gearhead and the guard will be designed in unison to completely solve the very annoying problem of long stringy grass wrapping around the gearhead and stalling the brush cutter. The design of the guard-gearhead combination will also make it easy for long grass to fall over the top and out of the way saving on power being wasted dragging long or wet grass inside and around the guard.
IT WILL HAVE A SPECIALLY DESIGNED GEAR-HEAD, to get the most from the power and torque of the Honda GX35 4 stroke engine. It will also incorporate an anti-vibration rubber mount between the gear-head and the shaft. This is to help reduce blade impact shock being transmitted up the shaft and to reduce engine vibration being reflected back up the shaft.
The gear ratio will be 1.5 : 1 meaning the engine will do one and a half revolutions to one revolution of the blade, which will also help reduce overall brush cutter vibration. I have been working on the design of this gearhead for over four years now, but have not had the resources to get it manufactured. Details of the refined gearhead will replace these one shortly.
This gearhead will not be lubricated with grease like all gearheads from other manufacturers, but with a high quality Hypoid Gear Oil. When researching hypoid gears, I found a paper that says hypoid gears should not be lubricated with grease over a certain gear mesh speed and of cause brush cutter gears exceed this speed. This means that with the high speeds, the grease is spun out against the housing walls and the gears are not lubricated properly leading to a much shorter life. Hypoid gears are smooth and quite running because the meshing gears are a half rolling, half sliding action. To get long life from these type of gears, requires a continuous supply of a high quality, high pressure grease or oil.
IT WILL BE DESIGNED TO TOTALLY ELIMINATE, the problem of long stringy grass wrapping around the gear-head and stalling the brush cutter. Read & Watch More Here
This can only be achieved by the gearhead, guard and blade all working together in unison to prevent this annoying problem.
The spiral design will give better and safer control of the machine. The unique spiral design of the loop handle will provide a good grip in the normal position and on either side and reduce vibration to the hand. Read Hear To Find Out Why
This design will also allow you to get a wider swing than can be offered by most bicycle handle brush cutters, when clearing long grass and weeds on flat ground.
Since there has been no improvement to this design since the first brush cutter came out over 16 years ago. This custom housing will also incorporate a counter balance weight, that will perform three jobs.
FIRST, it will help offset the longer shaft and the extra weight of the heavy duty blade, gearhead and guard.
SECOND, this weight will be low down under the engine, to put the centre of gravity back through the centre of the shaft. This will stop the brush cutter wanting to roll upside down if you let go of it when it is still suspended from the harness. This can be very dangerous, as it can leave the exposed spinning blade facing upwards without a guard covering it.
THIRD, this weight will act as a vibration absorber, helping to soak up vibration that gets past the engine-shaft rubber isolator. It is not really possible to soak up engine vibration with a rubber isolator alone, extra mass is required. With a car, the engine is perhaps about one tenth the weight of the car and so engine vibration only has a very small affect on the car body itself. With a brush cutter, the reverse is the case, with the engine weighing much more than the shaft of the brush cutter. This means the engine, easily shakes around the shaft and handle grips of the brush cutter.
I discovered this after adding counter balance weight to the engine base plate of the second brush cutter on which I tried to improve the balance.
Adding extra weight to the engine only lowered the frequency and increased the amplitude of the engine vibration. Also the extra weight of the engine, means more vibration gets transferred from the now heavier engine to the lighter shaft and resulting in more vibration to the handles which was not the desired outcome. I discover that to get the desired vibration reduction, the counter balance weight needs to be added to the shaft.
Trigger Control Handle
Designed with silicone isolators to reduce vibration transmitted from the shaft to a minimum. This is to suit the longer operating hours faced by those with larger properties and commercial operators. The kill switch will also be shielded so that it cannot be accidentally switched off or broken off.
With four screw to clamp tightly to the shaft so that it does not move from its correct centre of balance position. The hitch is bottom weighted so that the mounting hole is always facing upwards and the bottom is shaped so that you can hold you hand on the underside of the hitch to easily align the mounting hole with the harness hook. This solves a very annoying problem with this style of swivel hitch.
The ball shape will also provide a good pivot and rolling surface against the harness rubbing plate as you swing from side to side and rotate the brush cutter on either side.
But it will have a clutch housing to suit a Honda GX35 4 stroke engine. You will have the choice of either buying and fitting a cheap Chinese copy Honda engine you can purchase online. Or preferably going to your local Honda dealer and buying a certified Honda GX35 4 stroke engine that meets the regulations of the country you live in and that comes with the Honda 3 year commercial warranty. This will make the new BrushDestructor machine, more affordable in the South American, Indian and Asian markets, where because of affordability issues, there is a high use of the cheaper Chinese copy Honda engines.
At some stage in the future, when battery technology gets to the stage that it can power this machine for a good hour or more and as it becomes more affordable. I will be looking at designing an electric motor and battery unit that will bolt straight on to the clutch housing unit. So that if and when you decide you want to change to an electric power source, you can do so without throwing the whole brush cutter away.
EMF FIELDS FROM ENGINE; is something that I will be looking at eliminating. I have been aware of Electro-Magnetic Fields for some time now, because of the time I spend in front of a computer, but Electro-Magnetic Fields is not something that I would have associated with brush cutters and I don’t think anyone else has made that association either. Below is a picture of my Honda brush cutter running at about half revs and on the EMF meter you can clearly see that the magnetic and electrical fields are maxed out. Yet the High Frequency Waves are not registering anything, as we live in an area with no mobile coverage and we have no blue tooth in or around the house.
What causes these fields is the engines ignition system, there is a very powerful magnet spinning around that creates an unnatural alternating magnetic field and the electrical field comes from the build-up in an electrical charge in a coil to the point that it caused a charge to jump across the spark plug. What makes this such a problem with a brush cutter, is that all of this takes place within a few hundred millimetres of you kidneys and liver, where all of your blood is flowing through for filtering and cleansing. I cannot think of another garden or power tool for that matter, where the source of such large EMF field are so close to the body for such long periods of time.
I had started feeling short of breath like someone with emphysema, but after an x-ray cleared any lung problems, I then suspected that it may be from high exposure to EMF. There are various affects that EMF can have on the body and the one that is relevant here is the affect it has on our blood. The high water and iron content of the blood makes it the perfect absorber of EMF and conductor of electrical charges.
If you have read my page on Hand Arm Vibration Syndrome, you will have read how vibration can cause capillary veins to restrict reducing blood flow. Now if your blood viscosity is thickened, it becomes increasing more difficult for the blood to pass through many of the millions of capillary vessels depriving those areas of much need oxygen and the removal carbon dioxide waste.
Clumping of red cells called rouleaux effect, and is where red blood cells clump together making the blood thicker. The two main negative effects of this, is that the red blood cells can no longer effectively absorb and carry oxygen to all parts around the body and pick up and remove carbon dioxide and other wastes to be transported to the lungs, liver and kidneys for removal from the body. The other problem caused by these large clumps of red blood cells is that it makes the blood thicker and more viscous, making it difficult to travel through capillary blood vessels and depriving those areas of blood. The picture below shows on the left what normal red blood cells looks like, it has a good viscosity and is easily pumped around the body by the heart. The picture in the middle taken with a scanning electron microscope, shows how the red blood cells have all clumped together from the higher electrical charge in the blood. The picture on the right shows where the blood was so thick, that the pressure of it being forced through small capillary veins has ruptured that vein.
If left unchecked, this can lead to all sorts of health problems, with the most immediate problems being heart attacks and stroke. A much thicker viscous blood is more likely to drag plaque loose from artery walls where it can cause a blockage somewhere else.
I was able to get hold of a powerful microscope where I checked my own blood and it was indeed like the photos shown in the middle. This microscope did not come with a camera, but I found an image that exactly resembles what my blood looked like in that microscope and is shown below.
IT WILL BLOW AWAY ALL OTHER BRUSH CUTTERS, including the commercial machines from Stihl, Husqvarna, Shindaiwa and Echo. Because unlike these other manufacture, where brush cutters is just a drop in the ocean of their overall business. My business is only brush cutters and I will always be striving to improve the design to the point that no other manufacturer can keep up. Read Review of other brush cutter Here.
I wonder how many of these features will suddenly start appearing on other brands of brush cutters, especially those that ignored my emails. just remember, you read about them here first.
Please come back to this page as there will be a lot more details to come on the new BrushDestructor Machine.
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