Shredder development – bigger one

Hello ,
I would like to develop a bigger shreddder . And first of all . Im asking myself why not to post it over here.

Second one – I want to build it to shred bigger parts / harder parts than bottles.
I would do something like on the pictures, if you like then Ill send You some 3D drawings of it.
This design I have found online . But I would like to modify it to achieve best results.
I have attached a pfd. wich tells something about desiginng a blade of a schredder.
( I dont know how precious plstics team have developed actual knife, witch is not suited for heavy duty work )
If you will have some comments , fell free to join the discuss.
Peace from Switzerland

This is a great project! What kind of plastic items are you thinking of being able to shred with this?
I know absolutely nothing about machine building. Although to me it seems as the blades are facing the wrong way in this machine? Am I completely wrong??

@malyboa, will be back to you these days 🙂

what kind of clearence did you mentioned?

Take a look at this picture, wich I attached to this post.

You are tlking about plastics in EU …… I have lot of requests to build an shredder for :

– CAR PARTS ( Car Plastics like bumpers , cocpits ets… )

– Wires  ( tons of wires, cables )


Thatswhy i Need bigger dimention of working area. But without any tests it would be hard for me to guess it this design is good enougth …


not knowing the diameter of the blades but i’d say you need way more clearance for your knifes, the proportions you have now won’t cut much plastic, just moving it around 🙂

Dave’s design seems to work ok with a clearance of 3cm, i’d say 5cm would be best fit for most plastic you can get here in the eu but you will need also a stronger motor, 5Hp, and more thick knifes. sorry dude, but it seems rather like back to square one to me (i can be wrong)

Im doing and thinking about this concept…

something is wrong here , but I dont know what…

Hi. Anne-barbier ( thank You for the anserws ) i switched back to simple blades. And i have buildt the 1st stage of the shredder. It could be build longer … when you will add some Blades to it.
i have tried to make most of the parts of 10mm sheet steel.

i think you could even use recycled aluminum for the blades, it’s a hell of a job but definitively doable, the knifes though could be done on the bench grinder 😉

great! that’s the way, only problem is that it more likely won’t work with a plunger in the hopper, at least when it comes to common house hold plastic, that’s why dave’s blade are that big though

Hello everyone.
I wanted to do some progress on this project but I could not.
Rigth now im back , stronger than before.

I want to show You 2 pictures of the new design . Its not ready , but one step after another.

on the pictures You can clearly see how its gonna look like. I want to use blades that have 150mm in diameter. Every “cutting plate” has on it’s ends a BLADE – wich would be screwed on it – from stronger material. ( I cannot say if this idea is better ) it’s not simplier – but it could be good….

next update ( comming soon )

Hey @malyboa thanks for the drive link, precious information on there indeed !

Hello Again my dear friends.  Thank You very mutch for commenting my topic. This is helping me to make rigth choices.

@andyn – I never told that my design would be innovative or somehow better. I want to develop an OpenSource simple but efficient shredder that wouldd allow to shredd some bigger parts.

If Youre familiar with Shredders- then You know that this machines are reallly EXPENSIVE . Only companies are owning them.

Over here : Baza wiedzy – Google Drive  files with some knowledge for us all.


Peace folks !



There’s nothing particularly innovative or special about my ‘design’ and nothing that hasn’t been done before, so I can’t lay claim to anything.

If I were to build another one it would probably be different as I just built it using parts and materials I had to hand. It evolved more than being built to a particular design.

Hi Malyboa, are you able to make little change on the actual cad files? I think the blades must be changed too, but at the moment I think it could be possible make little changes to avoid the assembly problems that all people have found….If you are interested we can discuss on private or here too.

Cool topic! I follow closely 🙂 Here 2 shredders hacks that might be interesting to look at. Big shredder indonesia Big shredder US

@andyn @malyboa @jegor-m @fabirihotmail-com Why dont we just upscale andyn’s Design as his shredder is double cutters and all we would have to do is the scaling that is relative. (Thats if you dont mind andy)

Hello Guys.
I have been thinking a little about the design of the Blade. Wich is one of the most importand thinkgs when You want to build an Shredder.

I wanted to build my Blade with wedge smaller than this one from precious plastics…

Blade is still – Work in Progress. But this is the first stage.
(sorry for my english)

everyone of YOu is rigth , BLlades are facing wrong dircetion. As I mentioned if before , this is an project from the internet. Ill try to upgrade it . and make possible for us to build it.

Yes, the blades are in the wrong way or this is just a upside down view.


Design development is always welcome on this forum.