Shredder Design…

Hello folks,

I am wanting to build some of the PP machines on an extreme budget, starting with the Shredder.

The first limiting factor I’ve found is availability / cost of CNC laser cutting services locally. I’ve toyed with the design in CAD and have an alternate that is built only from parts that can be hand made in a non-cnc facility like my shed.

Problem is, I don’t know what I don’t know and so thought it best to put the idea up for comment before spending time and money building it.

I was also planning to put a square drive on the end of the main shaft and plug my pneumatic socket driver onto it so it would be powered by a compressor rather than an electric motor.

So, where am I going wrong most seriously?



I would say that the idea of using a pneumatic impact driver isn’t a very good one, as impact drivers don’t deliver a constant amount of torque. it delivers it in peaks, which wouldn’t work in the scenario here, because the plastic would act as kind of a spring, minimizing the effectiveness.
I would use a hand crank and a flywheel with a gearing to decrease speed and increase torque as a simpler option.

Also, the shredder blades would most likely push the plastic away from the center as it shreds, i would recommend having a slight curve to them, to push the plastic into the middle, making it more effective

hello @pcal

your design looks good, although I do not know much about this, maybe I would modify this angle so that it does not push, and I would put a motor with reducer at low RPM