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Shredder on a wooden table isn’t probably the ideal solution. If you go this route I would recommend bracing it HEAVILY. More info here:
I’ve been down the rabbit hole with the bike powered shredder. I will not say pedal power won’t work. But I will admit that I started from the wrong place. The Schwinn frame, while common by bike standards, is the absolute wrong solution for a shredder frame. For anyone looking to try it, I would recommend using the bike frame from the bottom bracket back, and building a custom frame for the front. This would allow a much larger flywheel, stiffer, more torsion-resistant frame, and easier fabrication.
Suffice to say I’ve figuratively and literally scrapped plans for the bike shredder. It was costing too much to have someone else experiment. I bought a used motor and gearbox locally and am having some couplers adapted. I made a table for the stuff in the mean time. Looking forward to having a working shredder, even if it is electric powered.
I’m tempted by going to a motor too, but if your school has a welder in the shop area, it might be worth fabricating a hand crank with a large flywheel.
There are a few YouTube videos about hand crank shredders. The one I liked (https://www.youtube.com/watch?v=3Q8HE_6JMpU) eventually had a 5:1 gear ratio with a 40 pound, appx 3 foot diameter flywheel. They put the flywheel on the shredder shaft at about 10 RPM, but I’d put it on the crank shaft instead since it runs at 50 RPM. I think they went to chain drive after the belt slipped too much.
I’m working on a pedal powered shredder with a 20″ flywheel of a similar weight, although mine will hopefully be heavier. I anticipate a 90 rpm operational speed at the flywheel, with the shredder rotating at as low as 20 rpm (4.6:1). Bike chains and cogs are great for availability but unfortunately you will be limited to between 13 and 65 teeth unless you gear down in two stages. 65 tooth chainrings, to my knowledge, are only available on Schwinn Exercisers which were made from 1966 to 1982.
Here’s my thread: https://davehakkens.nl/community/forums/topic/looking-to-construct-a-shredder-out-of-plastic/ and my blog which has more info/pictures is plastic.linnerdesign.com.
I can sympathize with your interest in a motor. But if you decide to continue with human power I’d love to see it. Actually, with a bunch of kids around, why don’t you run it off a capstan? Recess will never be the same. 😉
Oven control box is installed. I need to find the clips for the controller and contain the wires on the back. It will also need a more robust power plug since the plug on it right now is pretty beat up. But it does work, so I’m hoping to drop this oven back off this week for mold fabrication and pick up the shredder (hopefully operational) to shred things. 🙂
Also useful: I had the fabrication shop build some wheels (from an exercise bike) into the frame so I can move it around. My garage does not have much room so moving this in and out of its storage location is important. I plan to mount the extruder underneath the jack and the injection molder on the side of the oven frame so the ‘making’ type machines are all-in-one.
Thank you! After fighting off a cold over the weekend I finally got the shredder over to the welding shop to get the heavier flywheel fitted and have a couple other things done. I then brought the oven home so I can fit the control box over this weekend. The mold hasn’t been started yet, but the shredder is a higher priority anyway.
In other news another Precious Plastic member reached out to me! I have brought him over to see the machines a couple times and will be working with him going forward. It’s good to have someone else here in Flagstaff who is interested.
I’ve had a couple other things happening lately but will hopefully have nice photos of the oven for you all this weekend. Cheers!
New chute in progress. Video tour in link below.
Work, work, work
Also looking at options for swapping out the flywheel for a heavier one. Trying to go from 11 lbs (5 kg) to at least 30-40 lbs (14-18 kg). This one weighs 20 lbs (9 kg) and has room for extra weights.
More tomorrow hopefully. I think the last things I need to do are the flywheel, finish the chute, and convert the lower chain tensioner to an actual idler from a derailleur. Two of those will need help from a fabrication shop. Ugh, I wish I could weld.
Shredder is home. It’s working but needs some tweaks to be ready to do real work. The main issues are gearing and a too-light flywheel. I’ll be investigating today. To avoid copying/pasting everything, check out my blog for the rest of the updates:
Quick update. I don’t know if image uploading is working so I’m adding links too. Shredder is almost done. Here is a video before the chain tension has been figured out.
Oven is 95% done now as well. Just need to find a control box, mount the controls, and also possibly move the thermocouple.
As I await the shredder’s completion, I am working with the shop that worked on the oven to build a sheet mold based on this: https://davehakkens.nl/community/forums/topic/slow-molding-sheet-making/
The idea is to experiment with making multiple sheets of different materials and thicknesses, and building a shredder out of them! No idea how it will work.
Dynamo hubs are readily available for powering lights. You will just need someone with wheelbuilding experience and about $40 per bike for spokes and nipples. Bike tourists the world over will tell you there’s no reason to to reinvent the wh- I mean… dynamo. 🙂
Cool ideas here. I may be a bit late to the game but I wanted to drop in and say I am submitting a grant tonight to build two of the machines as part of my masters thesis project. I aim to create parts for Precious Plastic machines out of recycled plastic, as mentioned earlier. I actually came up with this idea independently this morning, haha. Glad to come here and see some other people thinking about this stuff. It feels like common sense.
I think Precious Plastic USA is doing a great service and I intend to buy from them when I can secure some funds. However $85 for a shredder hopper is kind of nuts. If I could get that and a few other parts made of plastic I imagine I could cut off $100-200 at least. If the tables are able to be made from plastic, perhaps cut even more out. This would also prove that Precious Plastic is a useful endeavor, not just for art objects. I am an industrial designer so I understand the attraction to art, but as many are saying, art isn’t going to save the world! Making it cheaper for others to recycle plastic… well, that is one thing worth trying.
Also should mention I’m not looking to put Precious Plastic USA or anyone else out of business. In fact a partnership with a willing fab shop would be ideal because I have neither the tools nor skills to do the requisite metal work. I just want to help flex the muscles of Precious Plastic to make the whole initiative more accessible.
Some other ideas-
-solar thermal technology
-trike mounted workshop
Please send me luck on the grant!