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shredder build IDEA
- This topic has 41 replies, 17 voices, and was last updated 2 years ago by
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experimenting to find alternate ways to build.
The motor and its electronics specifically,
I noticed that garden mulchers/shredders have quite a powerful output, what I’m interested in is attaching the stainless steel shredding unit, to replace the barrel component usually found in these garden units.
garden mulchers appear to have a relatively small motor compared to the ones specified for this project, but most seem to be 2800watts, and (geared) much like a cordless drill .you can pick them up for £120 new.
whats good about them also is all the electronics are ready, forward/reverse/ with safety measures,
most come with a circuit break on the box, a clip which has to be engaged to make the shredder work. which could be rigged as a pull chord for extra safety, treadmills have this feature I’m describing.
There will have to be some cutting up of the existing body work to make things fit. but thats why you buy second hand. 🙂
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Interesting plan, would definitely good to have different options for the motor. Never worked with those mulchers but it would be a good option!
Keep us posted. The motor is really a big expense. If this works it’d save a lot of time and money
@snowpoff @dreek00 thanks, im working on getting all the bits together, they seem like they have enough power
its all down to DC motors and planetary gear system, like cordless dills manage some serious torque.
i cant find many images in of the inner parts to these garden mullchers, which is annoying, this is all i can find so far.
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In my experience Mechanics are wonderful at building and repairing. But are often lackluster in photography and documentation.
Keep at it. And don’t forget to document for the rest of us, haha.
@snowpoff i think i remember seeing that you need about 100nm for the shredder, well this claims to have about 650nm, and after further research in to gear boxes, the planetary gear systems you can buy for industrial motors are one of the most expensive, and categorised in heavy torque outputs which im guessing this garden mulcher must have.
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Honestly in hindsight, I wish I would have bought an electric garden mulcher/shredder versus building a shredder for the first go-around. You could buy one of those a lot cheaper than building one, although that’s not as fun and it most likely wouldn’t last as long.
I think part of the issue you’ll have is plastic is way more ductile and stronger than most “wood” products (branches, leaves, etc) so it’s a little different application. Still, there’s videos on youtube of people putting plastic through one of these types of shredders and it seems like it takes it pretty well, but you’d probably be limited on the size of what you could jam in there, versus this design.
This is exciting! I’m struggling to find funding for a shredder, this might be a good alternative if it works. Keep us updated 🙂
This garden shredder indeed has a dual planetary gear reduction and if you do the maths the torque comes out to 582Nm, not far off their claim. The blade arrangement is also similar to an industrial granulator as used for shredding plastic crates etc. I think this could make an ideal shredder (and much cheaper than building one). The only limitation might be the aperture for feeding material in is designed for small tree branches (45mm max) but looks like you could squash plastic bottles flat and feed them in between the toothed guard, or just remove the guard from the top. The wood chips that come out look a bit large, but I guess you could screen and re-feed plastic until it’s small enough.
@wess @veroes @andyn thanks for your interest, the plan here is actually to modify this commercial product with dave’s shredding unit, ive tried plastic through them, doesn’t work to be honest.
when you take apart one of these you find that the (tooth/barrel blade) is on an axle which just slots in with a keyway, think they are about 28mm diameter..
so all you have to do is build the plastic shredding box, and couple it to this,
i am very close to trying this, so when i have results il will post updates. 🙂
Awesome work! I’ve been watching a few clips on Youtube too with the garden shredders 🙂
so, finally have a mulcher to test, just need some jaw couplings now, ive measured the shaft on the mulcher, this ones 25mm at the end, and 32mm on keyway.
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update 🙂 @dreek00 @veroes @wess @snowpoff @davehakkens
i paid £60 for this garden mulcher, and so far (unmounted to table) it works” with milk bottle HDPE , its got a lot of power. but can’t be 100% positive until i make the frame to mount it on..
anyway, hope this helps in the quest for cheaper drives.
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that looks pretty smooth @kettlekekkers, thanks for making a video of it. Let us know how it behaves overtime, because it would be a good power supply!
@veroes it does ! Im very happy with its performance so far, dangerous amounts of power in that thing,… sure thing, id love to see another version of this, if you have the opportunity, the ( Bosch AXT 25 D ) could be a good place to start. slightly better quality than the Titan one i brought 🙂 you will need a JAW coupling to join the motor to dave’s shredding unit as there it a fair bit of latency in the axle..
i have a refined version coming soon so will keep you posted,
update, going to make a video soon, got some painting to do first.
I’ve mounted the motor to a frame which is re-cycled from a gym bench. and then mounted that to the original shredder frame,
all the electronics fit nicely in to this old tool box i had,
I’ve covered the motor with a piece of stainless sheet, as the fan in not enclosed,
nothing is welded on this, all bolted (try to avoid this as it takes ages)
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Very cool mr Kettle.
I had the same basic idea, but wrote about it in the “definite motor tread”.
Great minds think alike etc. 😉
I think these motors are the sweet spot in every way(single phase, cheap, high torque) except they are maybee a bit slow compared to the 70 rpm that was recommended. But a bigger hopper should solve that problem if it basically minds itself and don’t jam up to much.
Seems like Bosh is the only company that states torque, but as your experiment shows, even the cheapest of shredders should be good enough as long as they are of the right kind.
Looking forward to watch your video.:-)
@malawi https://www.youtube.com/watch?v=nACYxcfIvwA
ahh, indeed great minds do think alike and im just lazy, cant be bothered with electrics haha.
literally cant go wrong. though i find that plastic doesn’t self feed too well. its slippery so needs pushing down the hopper
The one that you have has a “tooth-barrel” that crush/grinds the wood, what about the model that uses knifeblades? Like the one on the pics. Think this one would work better?
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hi @ashrak sorry for the late reply, i don’t get notifications unless tagged unfortunately 😛
that type of shredder generally doesn’t have a gearing system, so it relies on the motors speed and fly wheel with sharp blades keep up momentum, so it will lack Nm of torque when applied to the low speed shredding requirements
tooth Barrel style garden mulchers are high Watts and double planetary geared down like a cordless drill , so they have hight torque levels.
🙂
< those ore ok for specific plastics and products for a certain amount of time, but the blades wont stay sharp for long, as plastic is more dense and consistent than wood twigs, you might as well put it through a lawn mower,
(DON”T though… haha ) !!!
but i suppose if you want to go even cheaper, and do no mechanical engineering it will suffice
@kettlekekkers I really love your build, but had some questions before I pick up one on my local classifieds.
If I understand correctly, you have taken a shredder/chipper/mulcher apart just for the motor and electronics?
Instead of using the chipper’s blades, you’ve coupled it to Dave’s shredder design?
@trent-robertson that is correct, i used the motor/gearbox/and electronics
i coupled it with a pair of jaws to compensate any misalignment.
@xxxolivierxxx thankyou! yes it does look a monster.
@kettlekekkers I was wondering how you separated the shredding gear from the axle (part 32 and 33 in the above exploded diagram) which way did the gear come off. It looks like all these garden shredders are pretty much built in the same way.
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