Sunday, 24 February 2008

Bosch AXT 18-35 quiet garden shredder review

This is the second of four reviews I shall be posting on my experience with garden shredders.

In early 2000 after my early experience with the small Al-Ko shredder I decided that shredding was a good idea, but I needed a much better machine if I was going to do much shredding without pulling all my hair out.

Drawing on my earlier experience I drew up a list of key purchase criteria, which were:
  • Able to shred soft as well as hard material
  • Easy to unclog if it clogs
  • Reasonably quiet and neighbour friendly
  • Cutting capacity of >30mm
  • Less than £250 (cheaper still if possible)
  • Easy to move around the garden
I had a look around the market and the quietness requirement seemed to be the determining factor – this limited the options to the low speed cog/drum cutters and Bosch’s spiral cutting system. At the time the cog/drum cutting system was fairly new on the market and there were only a few alternatives around. The only shredder that met my criteria was the Bosch AXT 18-35 (see photo below – not one of mine, but this one comes from Bosch publicity material for the current model which looks the same as mine), which is very similar to the current slightly more powerful Bosch AXT 2000 HP; even then it exceeded my budget by £10. The cog/drum based shredders were all considerably more expensive.

The shredder uses Bosch’s unique spiral cutting system (see diagram) with the cutting spiral working at the relatively low speed of about 160rpm. The “18” of the “18-35” model number indicated that it had a 1.8kw motor and the “35” of the “18-35” that the cutting capacity was 35mm. All the material to be shredded went into the same slot in the top of the machine.

It weighed in at around 23kg and its noise level was rated at about 84db. It proved easy to manoeuvre around the garden with its wheels and was blissfully quiet compared with the demented shriek I was used to hearing from the Al-Ko.It was also easy to catch the output in a bucket to keep the work area relatively tidy.

Performance when new
Not surprisingly the Bosch was immediately a massive improvement over the Al-Ko. It took in all sorts of material; the spiral cutter drawing the material into the machine, although it preferred relatively straight semi-ripe woody stems. It did block up with too much wet and soft material, but it was easy to unblock simply by reversing the spiral cutter’s direction. It was possible to jam the machine with dry hard wood, but again it was easy to clear out. I noticed that the rotary movement of the cutter tended to make long branches sticking out of the top of the shredder whip around a bit when not held, but that was never a real problem to me.

I have no record of how much it could munch through in an hour, but I did see a review in a paper suggesting that it was about half the speed of a drum/cog machine and I would not quarrel with that.

So I was happy – the machine produced good quality shreddings, relatively easily and quickly enough for my patience and the size of shredding piles we were creating.

How did it perform over time?
Well… after a Spring and a Summer happily shredding away I began to notice a significant fall off in performance. The shredder no longer drew material into it automatically and it was much more prone to blocking with fibrous material. The fibres tended to wrap themselves around the spiral cutter causing it to jam. Reversing it released it, but I had to put in some dry woody material to clear it out.

I talked to the dealer who supplied it to me and they exchanged it under warranty as it was not supposed to deteriorate like it had.

The new machine performed as the old one had when new (not surprisingly), but after a further year or so of use its performance too started to drop off in the same way. This time there was no chance of an exchange so after 18 months when it had become almost unusable I took it apart to check the spiral cutter. It looked OK, so I sharpened it with a file and put it back together again. (If you would like to see what it looks like inside then go to for a photo of a disassembled machine).

It was definitely better, but the improvement did not last more than a couple of months before it was noticeably worse again. This time I investigated the possibility of getting a new spiral cutter unit, but if I did the work myself the spares cost was about half of a new machine, which did not seem to be a bargain. Getting it repaired by a Bosch approved technician was still more expensive.

I battled on and finally took it apart again to really work out what was going wrong. It looked to me as if it was not really the spiral cutter itself that was the problem, but rather a clearing blade at the end of the cutter that was blunt and bent. This meant that instead of clearing the material from the spiral it was smearing it back into it, clogging up the exit. There didn’t seem to be a repair solution for this as I could not take it apart, so only new parts would do.

Since the machine worked OK’ish, albeit very slowly, with mature woody material I soldiered on until 2004 before deciding that a new, quicker machine was needed as the garden was really increasing its production.

This sounds like a litany of woes, but I worked these machines quite hard in the time I had them and they were OK for much of the time. If you want a quiet, relatively low volume shredder to use a few days a year then this one would be OK. In the eight years since I bought mine it may have been improved and it is certainly cheaper than it was (around £200 now, compared to the £260 I paid for it eight years ago).


Unknown said...

Again many thanks for sharing your experiences! I am also someone who expects things to work well and not just for a while, but for a long while, something our fast paced society has forgotten. The designing engineers are often not so interested in improving things , but in having something new to send to market - new name, new features, better profit margin and they don't expect to need to build long term following just make the sale, fill the immediate need. The consumer is often not well informed, so thanks again! Brian in Massachusetts

Unknown said...

An almost identical scenario to the one I have just acted out this afternoon. On the second dismantling I sharpened blades etc. but this isn't the problem. Something has either buckled, warped , worn down or whatever, which means the shredded material is just mulched up and spun round the bottom of the blade creating an impenetrable mush. Probably about 4-5 years of use, but even so I don't think it unreasonable to expect a little more.

Simon Woolley said...

Six years later and I'm in exactly the same boat! Spent last night disassembling the thing, clearing it out and getting it going. Still doesn't draw material through. Sounds like I have exactly the same problem. One more strip down, then lose it I think.

Simon Woolley said...

Six years later and I'm in exactly the same boat! Spent last night disassembling the thing, clearing it out and getting it going. Still doesn't draw material through. Sounds like I have exactly the same problem. One more strip down, then lose it I think.

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