Some groups may still need or want to use a small shredder. There are some people who like shredding but they do seem to be the exception rather than the rule. It's very noisy work so you must wear ear defenders. It has other hazards, bits can fly out of either end, so eye protection is essential, either goggles or a visor. Stout gloves and boots are also needed. The machines have safety features which lessen the chance of anything actually whizzing out and injuring you, unfortunately these features also make it more difficult to get the materials in and out of the machine. The exit chute particularly needs clearing constantly, otherwise the machine gets clogged up. Under ideal conditions most problems can be avoided. Unfortunately few of' us operate under ideal conditions. Chippers work best on freshly cut branches. Foresters and tree surgeons chip as they go, which is the best way to do it, from the point of view of handling materials, and using the machine efficiently. The fresher the chippings the more quickly they will break down. Very large branches will need to be pruned before they will go in the machine. Machetes, saws and long handled ratchet pruners are good tools to have. Sort out as much as you can before you start the machine up. Don't have it needlessly running whilst you go back and forth extracting materials to shred. Having a small team to supply the machine, a little at a time is the key to success.
The 8 HP bulldog machine, (which was initially supplied to groups in Devon before the advent of mobile chipping,) comes with two screens, small and medium. The smaller the screen size the more easily it gets clogged up. When I was running the Chagford project we never used the small screen and the larger one got blocked up so regularly that we had an even coarser grid specially made up by the manufacturers. Even this grid got clogged up and we were very relieved when the mobile shredder made it redundant for us!
When your machine does clog up, turn the engine off!
Don't leave it getting more and more jammed or you run the risk of burning out the belts, an expensive replacement!
Don't clear out the shredder chamber withyour bare hands. These are dangerous machines even when switched off.
Never operate without thorough training.
Manufactures' recommendations for the thickness of materials to put through the respective chutes are only a very rough guide. More important is the hardness of the stems. This is something you just have to gradually get to know. If you're not sure whether it should go through the shredder or the chipper, put it through the chipper. Some woods like cotoneaster; berberis and holly are very hard and only the very thinnest bits should go through the shredder, whereas great thick brussel sprout stems can go through with no trouble. It’s all a matter of common sense.
When a hammer does break, stop the machine at once. A loose hammer that doesn't go through the grid can whirl around taking others with it and they're not cheap to replace.
Firewood.
It can be much easier to put especially the larger pieces to one side to be sawn up for firewood. We often get brought beautifully seasoned sticks and branches which would be far better used up as kindling or logs than laboriously fed through the chipper and composted.
