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Stainless Steel in Shredder

This topic contains 35 replies, has 15 voices, and was last updated by  Crystal wang 9 months ago.

Bill billa14

Stainless Steel in Shredder

11/07/2018 at 15:20

Using Stainless Steel in the shredder is a real NO NO
I have been using mine for about 6 months now and has worn badly
The teeth have about an 1/8″ gap in front of them now so not cutting well at all and the sides well there is about 18thou gap on each side of the teeth to the guide
If you are going to build one please make sure you use a lot harder steel of some sort to lessen the wear

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01/08/2018 at 13:35

Well Mirco
I will have this to say in response to your message, I do appreciate what you have said and will everyones comments as they come in.

When we got this shredder made it everything was done by a laser cutter and it was fitted perfectly with very little clearance at all just enough to not grab or grind anything when turning  the clearance was very minute.

This shredder has definitely had NO steel any where near the machine let alone near the blades, it has had strictly plastic and plastic only through it.  How do I know this well I am the only one that uses it.

I don’t know if you have a shredder or have used one but a lot of the cordial bottles which are (no.1)  you put through have very hard necks and bottoms and quite often will jam the shredder if it is not cutting the plastic the right way, milk bottles I do are (no.2).

You said about the clearances we went by the PP specifications and built exactly to them.
It is 5mm 304 Stainless Steel that we used to build it. An engineer friend of ours advised that this might be good to use so we used it.
If as you say it was the wrong material why wasn’t it stipulated what to use in the instructions?
People like us go by the instructions because we know no better, so put all the instructions and information out together for us to build to.
As far as the screen goes I have never fitted one I just put it through 3 or 4 times to get the size I want so there is no problem as far as the screen goes.
Unless I am assured that there is a stainless steel that works a lot better than the 304 we used in this machine then I will be looking into something different to use.
The principle of the machine no doubt works well.


26/07/2018 at 08:27

Thanks for raising this questions @billa14
I was planning to order laser cut parts for a shredder yesterday and then read this thread and I’m now not sure what to do.
It seems odd that this topic hasn’t been raised by anyone before (that I’ve noticed anyway) as the shredder design has been out for a long time now. Is it possible that this is an unfortunate rare occurrence which has affected @billa14. I notice that he/she hasn’t added any further responses on this thread and there’s no detail of exactly which stainless steel was used or pictures of how the blades have worn. Have the blades got thinner (through rubbing the neighbouring blade) or just worn away along the cutting edge?
As has been pointed out there are many types of stainless steel. I don’t know a lot about metallurgy (I’ve forgotten most of what I was taught over a decade ago now) but based on this page it sounds like a martensitic type would be good.
Has anyone else reported a similar wearing problem?
Two related points to consider (touched on above):
Should we be applying a hardening process to the blades?
Would it help if the blades were sharpened? A 6mm wide leading edge can’t be the most efficient way to cut through plastic. Sharpening would also reduce the torque required but may result in faster wearing if the wrong material was used.

24/07/2018 at 19:00

@anne, it was just a thought.  My Spanish is pretty rusty and I am also pretty occupied, just eager to meet some Precious Plastic members in different Countries when the opportunity presents itself – no worries,

21/07/2018 at 14:21


This shows a wood plainer and someone changing the carbide insert.  I hope this helps.

21/07/2018 at 14:08

Please an example link to best understand.

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