Shredder blade design, why this design

Hi Guys,

After reading a lot about the precious plastics project and about shredders in general (which i want to start with building), i keep wondering why the design of the shredder blades differs so much of shredders in general found on youtube.

Can anyone tell me why the shape of the blades is this way? (thickness as well as shape) ?

And last but not least, why one axis? besides costs/complexity offcourse:)

Just thinking everything well through before buying parts!


Anybody? Please share you thoughts folks! 😀

When we treated it (super) rough a few bended, so just to be safe we went for 6.

Hi @davehakkens,
Thanks for clearing that up. Did the blades bend in your experiments with using 5 mm thickness steel instead of 6?

Hi @arrow1800 and @siemenc

Shredder blades are the way they are after many experiments. Mainly finding a balance between pulling in enough “new” plastic to shred but not too much so the motor can’t handle it.
And the ticker the blades the stronger, but also the bigger the flake output.
This size worked could for us considering the output we are aiming for vs the strength we need.

1 Axe shredder is indeed to avoid complexity as much as we can and easier/more affordable to build

There’s some other topics where people are wondering the same. And I haven’t gotten through all of them but in the ones I did, I couldn’t find an answer either.


Did you ever find out? I’m looking at the plans and am wondering about those thicknesses. Why are these different? Does anybody know?
Did you find any other shapes of blades?

Regarding the axis I guess you answered yourself. I would think it would add too much to the complexity.