It’s a common mistake to think that material such as hedge clippings and briars can be processed by a chipper. It can’t. A woodchipper works only on a solid piece of timber that the rollers can grip and that can be held against the static blade or anvil so the moving blades can chop it. If the material has insufficient rigidity or is contaminated with stones, soil or metal, it should be put through a shredder.
2 Size matters
Since you won’t want to spend more than necessary — or spend money on a machine that does not have the performance and capacity to cope with the waste your business generates — it is important to purchase the right size of machine. There are two basic categories of woodchipper:
L The smallest and most basic
machines are gravity-fed and may be portable, mounted on a small chassis for towing or mounted onto a tractor for powering from the PTO.
L Woodchippers featuring hydraulic feed are bigger. They can be towed, tracked or tractor-mounted.
3 Gravity-fed woodchippers
Broadly speaking there are two sizes of gravity-fed chipper. The smallest, mounted on wheels or barrows, are likely to have a capacity of about 75mm and can be moved around by hand. Lightweight and compact, this is the machine that can be transported in the back of a van. It will easily access narrow gateways for work in back gardens, making it ideal for landscapers undertaking garden clearance.
The other size of gravity-fed chipper is the 100mm-capacity chipper. This type of machine is either mounted on to a high-speed road chassis for towing or it can be tractor-mounted. Again, these chippers appeal to landscapers. They are also suitable for estates and golf courses where there is a fair amount of chipping to do within the one establishment and where a bigger, more expensive, hydraulic machine cannot be justified. Tractor-mounted versions can save a considerable amount where a suitable tractor is available to provide the power.
4 Hydraulic-feed woodchippers
These are the brutes — the machines are forcibly fed by hydraulic rollers gripping the material and taking it in towards the cutting mechanism. These woodchippers are for those with more serious amounts of work and typically start with a capacity of 125mm. They appeal to landscapers with a certain amount of tree work every year but not the sort of level that would justify the more expensive 150mm category of machine. The 125mm hydraulic feed woodchipper will tackle most of the material encountered during tree work within a landscaping portfolio. The machine may be on a road-tow chassis or tractor-mounted.
The next size of hydraulic-feed woodchipper is the 150mm category. It is by far the most popular size of machine used in the UK. They are ideal for tree surgeons, contractors and local authorities, and are likely to be capable of doing 80 per cent of the work encountered. Chassis-mounted, tracked or PTO-driven options are available.
Most manufacturers offer hydraulic-feed woodchippers in a category of 190-210mm capacity. This type and size of woodchipper is ideally suited to the larger contractor because, in order to get the most out of the machine and your money, you really need to be running a gang of workers. Such is the throughput of this category of machine that one team will cut the wood and another will feed the chipper. Again, these machines will be chassis-mounted, tracked or PTO-driven.
The biggest woodchippers have capacities of 250mm or more. These are monsters used for specific tree work where large limbs need processing or where wood is processed in large quantities for biomass fuel.
5 Watch the weight for road towing
All drivers who passed a car test before 1 January 1997 retain their existing entitlement to tow trailers until their licence expires. This means they are generally entitled to drive a vehicle and trailer combination up to 8.25 tonnes (maximum authorised mass).
However, if you passed your car test on or after 1 January 1997 you are limited to towing trailers up to 750kg unless you pass an additional driving test. Young people between 18 and 21 can take the test, but they are restricted to vehicles or combinations up to 7.5 tonnes until they reach 21.
6 Tracked woodchippers
Most manufacturers offer tracked versions of their hydraulic-feed machines from 150mm-capacity upwards. Such machines tend to be used by contractors. They are nearly always used for line-side contracts for Network Rail or power-line work for the utilities. The biggest benefit of these machines is that they are self-propelled and enable chipping work to be carried out in remote areas a good distance from the road.
In addition, a lot of tree surgeons, contractors and local authorities have discovered tracked machines also benefit productivity when working stands or lines of trees. In these situations, the machine can be driven through the stand or down the line and chip timber where it falls rather than having to drag all the limbs to the chipper.
The penalty, however, is price. Tracked woodchippers tend to be more expensive than the same size of machine on
a road-going chassis. A trailer is also needed to move the tracked chipper
to the site.
7 PTO-driven woodchippers
Available as 100mm gravity-fed, or hydraulic-feed with 150mm capacities upwards, these versions are capable of giving the same chipping performance as a chassis-mounted or tracked chipper. But they have no engine, so money can be saved over the purchase of chassis-mounted or tracked woodchippers — if you have a suitable-sized tractor available as a power source. They are popular with local authorities, contractors, golf courses, estates and others already running tractors as part of their machinery fleet.
An extra cost — but a turntable
reduces the risks of working on roadsides and provides the ability to turn the feed chute completely away from the flow of traffic. These units are popular with councils, contractors and tree surgeons undertaking highway work.
Look after your woodchipper to get the best out of it. Sharp knives or blades are crucial to the success of operation, so blades should be checked every time the chipper is used. Blunt or damaged blades should be sharpened or replaced immediately and regular sharpening — at an interval in accordance with the service manual — should be undertaken by the dealer or specialist sharpening service. This is not something you can do yourself with an angle grinder.
Other servicing should be followed according to the manual. There are likely to be two stages. Stage-one servicing, perhaps every 100 hours or six months, will include changing fuel, oil and air filters, plus changing the oil. Stage-two servicing will be required at less frequent intervals — perhaps every 500 hours — for the hydraulic oil, hydraulic filter, drive belts and anvil.
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