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Based on the first reply I contacted the electrical engineer that had wired up my motor and he assured me that it was properly earthed.
I then took another approach. Where I shred is close to the earth grounding rod for our house, so I ran a cable directly from the earth rod to the machine and I still had a build-up of static.
it isn’t apparent in the video, but my motor is connected to a Start/Stop station that has a contactor and overload inside. The whole thing was wired up and tuned by an electrical engineer so I am confident that he did it properly.
My initial plan after my coupler shattered was to get a much stronger one machined up. But having thought about it for a few days I now don’t know if that is the best solution. If I make the coupler too strong, and there is another jam, something else much more expensive to replace could break.
So I will be talking to a mechanical engineer about getting a new coupler built that has a shear pin. Then if there is a large load put on the machine again the shear pin snaps rather than the coupler.
I will add photos to this thread once I have a new coupler built.
Well, that didn’t take long 🙁
The component joining the worm drive to the shredder clearly wasn’t up to the job. I was just shredding milk bottles and the HDPE folded over to about 5 layers thick and the component shattered.
Has anyone done any calculations around how strong I should ask them to make it for?
Ok, here is my next update on my shredder construction log.
I eventually gave up on the pedal-powered design. I am not saying that it is not possible to have a pedal-powered shredder, but for someone like me who has no mechanical experience I found it beyond my skill and ability.
So I have moved on the an electric motor driving my shredder. I have done a bit of a video here – https://www.youtube.com/watch?v=d_6kiNuszV8
My next step is to use a heat press to make plastic sheets and a CNC Router to mill the sheets into jewelry. I will provide additional posts around that process as it goes.
I am investigating making smaller, detailed jewelry using CNC Router and HDPE plastic. I don’t have any of the hardware yet, so I am hoping that someone with experience in CNC routing can give me some advice regarding the success of fine milling with HDPE?
Awesome! I have the same problem.
Thanks for the updated files 🙂
Happy to provide input from an Australia perspective. I am also able to provide some input regarding pedal-powered shredder if anyone is interested.
Hi @jacobroy-quebec, sorry for not replying earlier.
I will send you a photo of how the gear is attached to the shredder tonight when I get home from work.
Hi @katharinaelleke, no, I have not really improved on the design. The whole idea of this design was to provide a cheap shredder while I get the whole thing up and running. I am trying to build up the courage to do the injection mold next. Once I have that going and I am making items, I will see how they are accepted. If I am able to get some interested (and associated income) then I will be replacing the pedal-power with an electric motor.
It took a while, but I finally managed to get a video of the bike in action. Sorry for the quality, there is only so much you can do with a mobile phone.
Anyway, here is a link to the bike in action….
@saluc42, I am hoping to post an update video this weekend. In the photo that I posted, the bike was in an extremely rough state (I am not exaggerating when I say that parts of it were being held in place with tape). I have made a couple of changes thanks to the feedback I have received which has had a positive impact on the machine, positive enough that I will be spending the time removing the tape and making it sturdy. Once that is done I would like to create a video for peoples reference and comment.
I will note that I can’t promise that I will get it completed this weekend. I live in a part of Australia that has been experiencing some significant “rain events” over the last couple of weeks (with over 300mm falling over a 24 hour period a couple of weeks ago). We have a chance of another event this weekend and if there is a lot of rain my working area becomes a bit of a river.
I have put together a pedal powered shredder (though it is still a work in progress atm). You can see my post about it here – https://davehakkens.nl/community/forums/topic/my-shredder-construction-log/#post-69761
Ok, post 2 of my shredder.
I had been inspired by another post that mentioned hooking the shredder up to a bicycle, and I thought that this would be a good start as a proof of concept. So I purchased an exercise bike for $10 from the local tip shop, a steel frame that someone was selling at a garage sale, and after much modification, I have put together the following shredder.
I managed to get it to operational stage this afternoon, and though it does successfully shred, I find it very difficult to get a constant peddle action going. As soon as I drop plastic in, the resistance makes it too hard to pedal. I suspect/hope that it is just a case of getting the gear ratios correct, and I am wondering if there is any engineer who can help me with this because I can’t get my head around it.
As you can see in the photo, the cranks have one large gear. The Shredder has one small gear. The middle axle however has a rack of five gears on it.
Currently I have the following setup:
Crank to Large gear on axle & small gear on axle to shredder.
Is there a better settup that will give me more power? Any engineers/bike gurus who can give me some advice on this?
This might be a bit late, but I recommend against getting a crow bar or pry-bar to use as the axle.
I did the same thing, but as you are no doubt aware, the axle needs to be milled at each end down to 20mm to fit into the bearings. So I took the Pry bar down to an engineering company in town to get a quote on the milling.
It turns out that because the metal in the Pry bar is hardened, the cost of getting it milled is about twice the cost of them making an axle themselves because they will go through a heap more tools to mill it. FYI, mine cost $150 + gst but I got an extra modification which added to the cost.
This post inspired me, and I am in the process of building this.
I hope to have it finished in the next 3 or 4 weeks. I will post info when it is done.
My machine is cut with HA250 Plate steel. It all arrived today, but I am at work and can’t check the accuracy of the thickness – I will provide an update later re: that.
The way I see it, this project is a new concept. Dave Hakkens has done a good design to start with, but with any open-source project, once more minds get involved, with different perspectives and ways of thinking, the designs evolve. It is still in the Proof-of-concept stage. I suspect that the designs will morph – I have already identified an improvement to the internals of the machine to make obtaining the hex bar easier and cheaper. Other people will have other ideas.
Once I get the machine running, I will then start on the Injection Machine. Once I have got that up and running, I will be getting templates made and using them to make items to sell at markets. I will not know how they will be accepted, or if there is a market for them until then.
At this stage, I don’t want to spend a fortune to get a gold-plated system, only to find that the market isn’t there, or that a better design had evolved that is cheaper/easier/more efficient etc.
If I find that there is a strong market, I could then get the internals replaced with stainless steel (if required) or even replace the entire machine. Until I have established the market, I don’t want to get a premium system (eg – stainless over mild steel) because the risk is still too high.
That’s my opinion anyway…
Thanks for the heads-up! I have modified the cad files to 25.5mm. A small amount of tolerance will be ok.
I will have to buy a crow bar – I will take my measuring tool in with me to make sure I buy one that seems to be the best fit.
I have now come to the conclusion that I am not going to be able to get the 27mm Hex bar easily or cheaply.
As an alternative for my Proof of concept I have reduced the size of the hex in the blades to 25mm. This matched Hex bars used for crowbars so I will be able to get a crowbar to use. Hopefully the guys at Express Metals have not cut them yet and I will be able to get the updated ones instead.
If you would like me to send you a copy of the files that I used, please let me know.
I am in Australia too and was quoting AUD prices 🙂
$1600 seems a bit on the expensive side to me. I am looking at paying less than half of that for the shredder (and I don’t have anything for milling etc).
What is costing you so much?
I have not encountered this issue yet. I will be doing milk bottles to start with and they have the plastic stickers.
In saying that, I did create a bottle cutter for upcycling glass bottles and I encountered this issue with wine bottles. For the Wine bottles I had to soak them in hot water and then scrape as much of the glue/sticker off as I could with a knife (a butter knife was the most efficient). I then used Eucalyptus Oil to clean them up.
I did have to get the bottles perfectly clean so it was a tedious job. You could possibly get away with some glue residue left over with the plastic?
I have AutoCAD on my PC. Is it sufficient to just change the Units from mm to cm, or is there some additional changes that are required?
Any advice will be appreciated.
Ok, I think I have more of an idea of what is happening here….
When I open the .dwg files, the Units value is Millimeters. As a result, all of the images would be extremely small, too small for printing.
Can someone tell me what the Units value for these files should be please.
Which files did you send him? If it is the files with the .dwg file type, he can open them with autoCAD.
In saying that, when I open them (I have AutoCAD 2015) I do get an error message appear advising that the NLS files required to convert the text entities and symbols cannot be found, but I click on Yes to continue and the files still open.
Another thing he can do is view the files via the following website:
Hope that helps
I have been having the same problems as you re: finding an electric motor.
While looking online I identified what might do the job.
Old electric cement mixer motors. I will be investigating further, bus as I see it, they will have to be 1ph (usually plug in so can’t be 3ph) and considering the job they are designed to perform, they would have good torque.