Building a Hand Cranked Shredder for Recycling Plastics 💪

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Let me show you how I built a hand-cranked shredder for recycling plastic waste. I want to use the shredded material to 3D print new parts from it. The shredder was sourced from the Precious Plastics Bazar and delivered as a box of sheet metal parts. Assembly was quiet easy only getting a proper hand crank was a challenge. I ended up with a 80cm long 25x25mm steel tube that is attached to the shaft via a laser-cut adapter. Similar particle size is very important during the process so I designed stackable and 3D-printable sieves that are used to obtain the different particle fractions.
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[@CNCKitchen]

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[@hyperhektor7733]

you could use a reduction gearbox(1:12-15) + a drill or cordless drill to speed up the process, one other comment suggestet to preheat the parts like 60-100degrees (?)

[@ts3dprints732]

I was thinking a bicycle/motorcycle gear reduction could be made to help out. Maybe a concrete base to weigh it down and hold the gear reduction. The molds for the concrete could be 3d printed.

[@coolfrost6]

Teaching tech seemed to have good success using a cheap electric winch

[@feds27]

This idea seems good for a 1st pass before feeding the line through a filament former. www.kickstarter.com/projects/910418035/plastic-bottle-cutter

[@TheBowersj]

can you mix different plastics together and do a strength test on them, maybe you can make a stronger plastic yourself?

[@Ic3Fenix]

You should consider replacing the long lever with a gearbox to make the spinning easier. Good job for the project :D

[@LordtwoDark]

Great idea, maybe a worm gearbox? you get allot of torque out of those but you need more rotations.

[@Ic3Fenix]

@@LordtwoDark With this setup he doesn't need it, spur gears are more efficient and the gearbox will be compacted, saving a lot of space. I'm a mechanical engineer as he is, it will be easy for him to do the math for this upgrade

[@lucaseyraud4031]

Yeah just two gears with 5:1 ratio or more would make a huge difference. You should find some easily on Internet with the proper axis diameter... Well done anyway, I was planning doing the same but 350 is quite expensive for myself.

[@kyleadkins2717]

I was going to suggest the same thing, i was actually going to suggest a real big gear reduction and then hook that gear reduction to a small predator engine. Predator engines are dirt cheap at harbor freight and they tend to have decent torque at the rpms they can run. Im not sure how well vented this shop is but a small predator engine with a big gear reduction with those blades would chew through most any plastic i would suspect. Ive seen the blade systems that precious plastics make and almost bought one myself for fun but i just dont need it but during the process of thinking about it i was curious on how to solve the 220 motor problem. For the home shop that doesnt have a welding power drop at 220 an electric motor just isnt cost effective. Then you have to consider the motor controllers and safety from such a system. Going to an internal combustion would solve those problems real quick and you wouldnt have to mess with complex electrical issues and you would likely get a more stable torque since you could add more fuel for more power.

[@LFdu83]

This, and a ratchet so he can push the lever up and pull with his own weight

[@santiagoblandon3022]

You recycle and do indoor exercise at the same time! perfect for this times of quarantine =D

[@sambarnes1226]

The things people are doing with THIS sudden mass of time available

[@lordkahtu96]

Take the "trash" particles and melt them on a hotplate into a puck then re-shred the puck to proper size particles.

[@SkaveRat]

the problem is: there are quite a lot of metal shavings in there. you *really* don't want those in your final filament

[@kelpygsus132]

@@SkaveRat You could probably use a strong magnet to sift them out couldn't you?

[@rizalardiansyah4486]

@@kelpygsus132 that might work

[@m1c4o]

maybe you can use water, the metal will sink, and the plastic will float

[@denispoppitz8323]

@@kelpygsus132 I think some part were made of stainless steel = only partly magnetic

[@matthewfeurtado8921]

It would be interesting to test the strength of a print after being recycled multiple times comparing each one to fresh pla

[@skyak4493]

In auto parts we had tolerance levels for regrind of sprues and runners. I suspect PLA will not tolerate much regrind because of the "annealing" behavior changing the melt temp. Molecular weight distribution affects melt properties and strength and every mechanical break of plastic cuts chain lengths. ABS was fairly tolerant.

[@JoeMalovich]

a 14 tooth to 72 tooth sprocket chain reduction would help for sure.

[@Mobile_Dom]

i'd love to see a review or at least a more detailed look at that pellet extruder.

[@CNCKitchen]

Will do!

[@foolishafraid562]

@@CNCKitchen I'd also love to see a review of the extruder. 3d printing with waste PET would give people a nearly infinite source of material.

[@roebyroeby1]

Hey@@CNCKitchen, or Stefan if you prefer. I'm curious about the performance of the Mahor V4, as I intend to buy it to make 3D printed prosthetics for amputees in Kenya. A local company makes recycled injection molding polypropylene pellets. Previously, I've already been using PP in the 3D prints because it's the strongest for the least amount of money. You probably can imagine that I've seen my fair share of failed PP prints, and had to optimize my printing process a lot. Eventually, by tweaking the design and getting a heated chamber, the prints come out excellent. I'm curious now if the Mahor V4 could achieve the same quality. If this were possible, I would be able to make prosthetics out of 100% recycled PP. I'm a big fan of your work, I learn a lot from your videos, could you please help me with this endeavor? Wish you all the best!

[@make.anything]

Awesome! I've been wanting to design a shredder like this, but the precious plastics prefabs sure are tempting. I just happened to source a beefy electric motor and gear train, but the handle solution is great

[@MatthewSchoepf]

Make Anything will you actually end up posting a video on it when it’s done ;) don’t forget about the filament maker.

[@xvico613]

Hello , we invite you to cooperate with our new 3d pinter model X5 , are you interested ? I also send you email .

[@gentiligiuliano7882]

I'm more worried of the price of the beefy gear reduction than of the beefy electric motor itself. I'm looking for a gear reduction rated for 500 Nm ... and they are expansive.

[@goldbunny1973]

Hi Stefan. Have you tried lightly warming the plastic in a microwave before tossing it into the shredder? That should reduce resistance without completely losing structural intgrity. Perhaps a geared link to the crank would increase torque & reduce back strain?

[@jakegarrett8109]

Might even do PLA in the winter (incredibly brittle, like I had my 3mm filament flying to pieces and showering my face and room like a frag grenade earlier today because it was so brittle coming off the roll...). So maybe for fun video get either dry ice or liquid nitrogen and dunk the part in it so it really explodes in that shredder (I think the parts should make a cool fog effect when they snap if they are cold enough and atmospheric conditions are correct). Useful? Probably not... But cool! (Im still not sure why the filament was so brittle, but warning it up helped a lot!)

[@goldbunny1973]

@@teeemm6415 A microwave could warm plastic by inductive heat; Stoneware can be heated to HOT by having something microwaveable in contact with it, so place the plastic in secondary contact and it'll be heated. You're not trying to heat it to it's melting point, only soften it's structure so it'll granulate more easily. Just my thought, could be wrong, can't test it as my microwave is currently offline : ) Someone could run a test tho..

[@Xiph1980]

Please don't do this. It makes it more difficult and you run the risk of gumming the entire device up. Freeze the parts, you want them to be brittle, not plasticized.

[@goldbunny1973]

@@Xiph1980 You're not "liquifying" the plastic. Can you test your freeze theory? Perhaps Stefan would like to try a few methods and make a video showing what happened?He's very good at Scientific Test comparisons.

[@goldbunny1973]

@@jakegarrett8109 LOL! Sounds like a video waiting to be made.

[@robertcullipher3492]

Add a powerful magnet in each filter stage to collect the metal shavings.

[@arrgh-]

water would have the same result, the plastic should swim. Update, I have to correct myself, water has a density of 997-1000 kg per cubicmeter, ABS has a density of 1030-1060 kg per cubicmeter, so per se ABS should sink :-(. Milk has the same density as ABS but I would not recommend it.

[@robertcullipher3492]

arrgh I originally thought water until I remembered how hydroscopic this plastic can be. Keeping it dry gives the most consistent experience.

[@fataxe1]

I thought he said it was stainless steel. Some grades have no magnetic properties, so a magnet may not work.

[@jjcc8379]

If those are stainless shavings there might not be of any help. Aisi 304 / 1.4301 , the most common stainless alloy , is non ferromagnetic . There are good ferromagnetic stainless alloys, but chances are a magnet won't help here.

[@arrgh-]

@@robertcullipher3492 just thought to divide the smallest parts from the metal. most plastic shouldnt be harmed and the water should disappear with the heating.

[@ThomasTheFapEngine]

Good to see people repping precious plastics. Nice touch trying the hand crank method, great video

[@alangregg7171]

i don't subscribe to many KZbinrs. While watching this video i realized that even tho i have watched dozens of your work, i had not yet committed to a subscription. I have always enjoyed your videos, and today you have earned it.

[@CNCKitchen]

Thanks.

[@wordreet]

Ah, I see you used a spiral flute tap at first. They are the weakest type and not really suitable for manually starting a thread in steel. Normally a hand tapped hole will require 3 stages. A start (first) tap, which has a loooong taper, so that it aligns itself with the hole. Then a second tap to form most of the depth of the thread, and finally a finishing or bottoming tap to get as much depth as necessary. For anyone reading this, if the thread is required all the way through, then the finishing tap is not needed.

[@hellelujahh]

Thanks, this is some great advice!

[@adama1294]

I would add some gearing to that lever.

[@mikemckittrick7872]

Greetings. Great video as usual. Here's a suggestion. Give yourself some mechanical advantage by adding a couple of gears. Perhaps a 3" dia gear at the shredder and driven by a 1" dia gear at the crank. Then you can reduce the length of the crank somewhat making it easier to crank while still having overall mechanical advantage.

[@SefPinney]

For your hand cranked version, I believe a precious shredder with ½ to ⅔ the blade gauge widths and a smaller hook area would suit a lower load human setup. It would still run fine with a smaller motor. “Not biting off more than it can chew.”

[@Randomguy_1911]

You could shred a bunch of benchies to create enough particles for a giant mixed color benchy

[@Dosman0026]

Really Cool! since day one, I have kept every failed print/support. So I can one day recycle it all.

[@OneArmyVideos]

nice one

[@trischas.2809]

First of all, you could shorten the crank by using a star-gearing. You would need to crank twice as often though. This also would have the benefit of possibly not throwing around the machine. Then, you need to mount it to the bench sturdier, but for a first test, this loos good!

[@alexanderthomas2660]

Nice. It's good to see a company selling tools specifically for recycling plastics. I still keep all the failed prints I have ever made, as well as little scraps like supports and brims, in the hopes of ever being able to recycle them into new filament.

[@rickyh2896]

would be super cool to see you build a gearbox for it! (probably not 3d printed but maybe a thick planetary gearbox might distribute the force enough to be partially 3d printed?)

[@madisondrum9179]

thank you! i was scared to buy it without seeing it first

[@pv8685]

ich hab den titel gelesen und hab mir gedacht: "ach im leben dreht stefan den shredder nicht von hand durch". dann hab ich den riesen hebel gesehen und da war mir alles klar. bist echt ein genie auf deinem gebiet. weiter so!

[@Zitropat]

Thank you Stefan and channel suscribers for this great project and their improvements!

[@McJohri]

Hi Stefan, did you consider heating up the shredder chamber? If you heat up the plastic to a certain point, where the plastics get softer, it might be easier to shred it. In that case, it would require less torque.

[@danielepellegri346]

what you say would cause the plastic to stick to the teeth of the shredder

[@McJohri]

@@danielepellegri346 I meant a particular temperature point where the plastic is not becoming liquid but a little soft like Klay but still brittle. Let's say about 50 or 60 degrees Celsius.

[@jeremyporterfield1611]

Just watching this - your sieves look and operate very similar to the aggregate measuring sieves used in stone mining / quarrying operations. As a prior materials engineer, one thing to note is that sieve hole sizes only guarantee your pieces are less than the hole size for the 2nd longest side of any particular piece - if you think about it, you could get an infinitely long piece through one of the holes as long as the 2nd and 3rd dimension sizes are smaller than the sieve. Granted, the space between the sieves in your "sieve stack" will limit this somewhat, but it's something to keep in mind while processing. Great video - really enjoy your thorough testing!

[@abbosbek7251]

Thank you CNC kitchen

[@wordreet]

I'm saving all my failed prints anyway. When I have a few kilos, maybe I'll send it to you.

[@Megabobster]

What I've been doing is saving the boxes the filament spools come in and putting scrap/waste back into it. Mixed colors go in with black since it will affect the color less. I've only used PLA so far but mixed materials would likely not be reusable.

[@wordreet]

@@Megabobster Oh yeah, I didn't mention that it's all PLA.

[@Akyomi777]

@@wordreet also good thing about PLA filament is that its biodegradeable

[@diegomolinaf]

Six months in the future, Stefan bumps into a friend: -Hi Stefan! Long time no see. What happened to you? You look like a bodybuilder! -I'm shredding plastic. -... WHAT?

[@aman11283]

You could go as far as to say at that point he'd be shredded.

[@frozenprakash]

5:58 First person every to tell the kW rather than in horses !! Wow, keep the great work : )

[@Aarmadale]

Paint the inside of the box with a thick layer of paint and add a strong magnet to the output to help with the contamination, and throw a gearbox on that handle!

[@mrMacGoover]

A simple reduction gear and built in hand crank would be from a boat winch that usually attach to the front of a boat trailer.

[@fooman2108]

Loved watching the camera doing the jitterbug on the table! LOL

[@theunholyghoster4293]

you should print some filament on the print bed from shredded material then shred it one more time to get even and soother print. that or make a cutter that takes the rough re-melted material and cuts it into the recommended size for you remelter another thing you can try is getting an arbor press and smashing all the prints you plan on recycling. this will make them thinner and easier to shread.

[@Sandwich4321]

You should add a big beefy gearbox to that

[@MixedGears]

Precious plastics has started a nice recycling project. Shredding energie, reextruding energie, filtering, cleaning, I wonder how big of a shop you should have to make a sustainable business. For example my filament provider, doesn't recycle neither theirs clean scrap, cause plastics behave totaly different after the first heat, second, I guess overalll is a very challage thing to succede.

[@robertt9342]

Seems like the flywheel you mentioned combined with some reduction gearing could make things a lot easier for you. Maybe include a spring mechanism to store energy too.

[@Barskor1]

Normally unusable plastics can be mixed with sand and or gravel heated and molded to form tiles and bricks add some carbon dust for UV protection and color uniformity you can tile your roof pave your driveway, garden path, the back alley behind your home and so on.

[@CKOD]

Their marketplace is an interesting concept for connecting local business that would normally deal with primarily commercial customers, to consumers. Rather than having to pester fab shops to find one thats willing and isnt givng you a "I dont wanna spend the time on this but will if you really wanna pay" sort of quote, you can find a place that is willing to do it, has the setup for the project done already, and understands whats being built. Plus the fab shop gets to use whatever resources they invest in setting up multiple times. (Only have to do the CAD on the laser/plasma cutter once, only have to dial in the kerf compensation once)

[@bobbylittle6996]

I worked with an industrial shredder 25 years ago for a bit. You definitely need a flywheel for that small shredder. Also a hammer-mill style is much better design so that it can retract the cutting head. That way the cutter head still rotates and does not hang up. When I need electric motors, I use one from an old washing machine, there tuff and cheap or free. The motor uses V groove pulley so you can make a simple friction culch to engage the cutter head. In case of a catastrophic stop the belt will slip, very safe. The company that made that shredder could make a hammer-mill cutting head small enough to.

[@KOWspazed]

Get some gearing on that handle! Maybe try printing them to see if they can stand up to it. If you're going to get a flywheel cut you might as well get metal gears cut at the same time.

[@reflector36]

i agree a gear reduction would be beneficial but i doubt a printer gear would survive the forces. I would watch him try, but i expect they would strip pretty quickly

[@CNCKitchen]

You could make 3D printed gears work if they are big enough, though the critical point is the connection to the shaft which has to be very strong.

[@user-po6hn9id1t]

@@reflector36 there are 3d printed reduction gearboxes that can withstand the abuse.

[@karlklops3810]

Good Idea. but i think the big problem are the way to agressive teeth of the shredder. Thats why its so hard to crank. if you compare it with the tooth profile of industrial shredders, you see the difference. :)

[@CNCKitchen]

That's what I'm thinking as well. Though the long teeth grab the parts way more effective.

[@KwaterbugBUTCHER]

You could get a small griddle and cook mats to remelt together the small bits that are to small to use , a strong magnet could pull out metal debris and garment vacuum(that pulls lint fluff off) could be enough for wood shaving

[@RomanoPRODUCTION]

Ya ya ya Thank you Mr Kitchen ❤

[@michal_c9007]

Use a garden shredder it works amazingly well

[@seabreezecoffeeroasters7994]

Have a look at using an Anchor or Yacht winch for your drive system as time doesn't matter that much in your case. DC powered will give you maximum torque near stalled state in a more compact size than using AC. Keep at it :)

[@3dprintingcave778]

I really like this idea of reusing the plastics and wish more people and business would get involved and come up with a solution that works very easy and be very cheap, if we had something very easy and cheap u would have people maybe going out of there way to pick up plastic pieces like bottles and straws whatever,,, I don't know how a mixture of all sorts of different plastics would work in a 3d printer,, but thank you for doing a video on this and I hope u keep going with it and maybe more people like you will jump in

[@manuelpadua2113]

Really late response but a quick fix for the metal shaving would be a magnet to sweep through it.

[@denTuke]

You could print a planetary 1 stage gearbox, the ones from gear down for what have proven to resist huge weights, so you could have a huge reduction and use a small motor

[@chrisdixonstudios]

An electric or manual boat trailer winch will easily crank the shredder! Your pellet extruder looks awesome..can't wait to see how you do that. Thanks for your efforts.

[@yonggor]

it's important for the shape of shredder to fit the uses. this shredder has huge but not so strong tooth, which should be good for breaking down thin and soft material quickly (i.e. polystyrene, pop can, cardboard). for 5mm chips and hand-cranked, the tooth profile should smaller and finer.

[@sipandrei6403]

Nice bike!

[@john-lucdiazirizarry4524]

Wow... I've never been this early! Sweet!

[@zanpekosak2383]

This may sound ridiculus to some folks but this could probably be done with a PTO shaft to have it tractor powered....plenty of power and will just keep on trucking. I have to start thinking about doing something like this....

[@laharl2k]

You need to pelletize the shreded plastic. It makes it easier to manager and mix and also dries it from any moisture it might have caught while laying around.

[@JSunBurns]

I want to build a machine to take spools of filament and chop it into consistent, uniform pellets by feeding the filament into a rotating chopper. I have some old spools that have taken on moisture, and my dehydrator doesn't do a very good job of drying them back out. I think if I cut them into pellets, I will be able to dry it better, then use it for extruding back into usable filament or using it for injection molding.

[@Xenu321]

I am thinking about doing something similar but for composting trash and garden material Thanks for sharing

[@thewulf7]

@CNCKitchen it would be really cool to see you do some materials testing on fresh material and then recycle the material once and repeat the test. Then continue to recycle the material and test to see how the properties are lost over time (or maybe they don't)

[@SidneyCritic]

Metal doesn't like rubbing especially stainless, it galls and picks up and gets worse, so it's best to fix the clearance.

[@BionicleFreek99]

I feel like adding a bit of gearing to increase the torque would make this work a lot better.

[@dimitar4y]

im sorry, but that lever... Oh my lord that lever. The effort. The sheer will.

[@baddog9320]

I think if you put a pulley system on your crank side. You can re- gear it and make the handle shorter. The huge handle must make it harder. By re-gearing you should make it use a smaller handle. Making it easier to operate. And may even make it more powerful..Though it will be slower. But in the long run. it will be faster because you are not fighting the operation as much.

[@Muzkaw]

A planetary gearbox is quite compact and you could rotate the other end with your impact driver

[@ejonesss]

i would add a 48 volt ebike motor like the cyclone motor witch their controllers can easily do 1600 watt and gear it down so it has enough torque to power through tough plastics. i do scrap metal recycling and i get lots of plastics from the stuff i tear apart such as air conditioners and shredding the plastics would be very handy as it would save space in the garbage.

[@Splarkszter]

you could use any motor or hand-crak length using metal gears

[@rverm1000]

What you could is use a car flywheel and starter. You would have an adapter made for the flywheel to shaft connection. I think a starter would provide the necessary amount of torque

[@m.schiller]

Use a winshield wiper motor or a garage door motor. They are verry small and have high torque. Also they can be powerd by a 3d printer or atx powerbsupply. And if it has not enough tourqe you can add simple gears and a chain.

[@andreyansimov5442]

If you look at professional shredders, it is totally different mechanics, blades, blades config and tolerance. It means everything

[@adammosonyi4671]

You might want to consider melting the to small particles down into a sheet and grinding it down again

[@madao7865]

That might expend more energy than producing/buying new material. I was thinking about a parabolic morror or something but you would need some contraption to distribute the heat and prevent overheating.

[@R_Forde]

@@madao7865 Maybe a solar oven would work?

[@madao7865]

@@R_Forde Good idea. One would need to a high end thing, though. I did a quick online search and most of them seem to max out at about 150° C. There are, however some that get up to 200 or even 300° C. One of those should do the trick.

[@Scootertuner420]

Hey. I just checked out some chinese companys how they recycle plastics. In general its very simple, the first extrude a thick filament thats than streched and squezed to desired diameter, than that filament runs trough a spinning blade so you get pellets again.

[@VictorTereschenko]

A lowering gearbox and a ratchet will be a nice addition

[@morrispicturestudios4458]

One thing you can do is to use a small washing machine motor along with gears to cutdown the heavy work on the motor but make the torch higher.

[@klyddmeisters]

add a massive flywheel that you spin up. And a flap so you can send down some materials when the flywheel is spinning fast.

[@another1commenter770]

Braze or weld a socket on the end of the shaft and use a mechanics impact gun to drive it. you can get them as electric plug in units but the battery ones are more handy but a bit more pricey. the air driven ones are good but too load and cumbersome with the air hose and stuff. the battery ones are about 1000-2000 ftlbs of impact torque and the plug in ones are 3000-10000ftlbs. Air ones range as high as you wallets value can expend. That and a fly wheel would work well. You might be able to borrow a mechanics one if you take you contraption down to a local engineering shop.

[@DanielRut]

Get a large ratcheting wrench and attach the tube stock to that. Then you dont have to do a full circle. You could get one with a switch, so you can go in reverse to help with jams.

[@birdmun]

To help find the high spots you could always use permanent marker on the teeth and rotate the cutters then file at the scrubbed points to knock down the high spots. Rinse and repeat until you don't see any bald permanent marker spots after rotating.

[@CNCKitchen]

Good point! Should have thought about that.

[@Benoit-Pierre]

Instead of long Strait funnel, you could do a short one either with a light lid, or a misaligned v shape introduction cone ( with proper alignment bouncing parts can't escape a V ). Donc use a fixes inertial wheel. Design it like impact drill : it can state a full circle, so that you can turn it a complete revolution before hammering the end. You may need a quarter circle mobile bit, to allow such a large movement.between two hallow.circles. Check how hammer drills work. Also check large vis used to press books in manual book manufacturies. The vis is actionned by a two element handle. The upper one is.used as rotating hammer against the lower one. Those presses offer tremendous amount of pressure with a simple.manual direct vis, without any geer or démultiplication.

[@Benoit-Pierre]

kzbin.info/www/bejne/b3nbhaZqmpqNq5I After 0:45 they give a rough explanation of inertial rotary hammers ...

[@Gees86]

I would use a 3:1 gearbox to power the shredder, that way the crank would be easier, and you could also use a simple 230 NM drill to power it as well.

[@wiredforstereo]

Even with the hand crank you still need a reducer gear box, at least 2:1, maybe 3:1. Whatever it takes to not have to back it up.

[@ftrueck]

you can melt the small particles back to bigger chunks so you can re-shred them

[@nottelling6598]

I'd of probably tried forming the smallest particles into a larger piece in an oven and then re-shredding it. Maybe use a short length of metal pipe as a mold and a weight to compress it in the oven? It doesn't need to be perfect, and gaps would actually make it easier to break up. The only other thing I would do would be to install some kind of repurposed gear-reduction mechanism in order to use a shorter handle so you wouldn't need to bend over to finish turning the crank. That looks like it could result in back injury the way you're doing it.

[@Jake_Productions]

here is an idea. if you get a nut attached to the end of the input shaft you can use a large pneumatic impact gun to drive it. pneumatic impact guns can provide up to 1200 ft lbs of torque so it should work.

[@ChrisRiley]

That poor benchy...great video man, thanks!

[@JoergGebhard]

You could use a wrench for moving the shaft so you could always apply force downwards. Or scrap a olt bike an use the chain to power the shredder

[@marksams1037]

Man I want your Mauser calipers! Those are awesome

[@antonwinter630]

thats fantastic. i didnt know about the PP marketplace.

[@johnnyricoMC]

Stefan, you mentioned wood and metal shavings at 09:35. I know some waste processing facilities separate the metals from other materials with a powerful electromagnet, perhaps that's worth a try? The wood shavings might be trickier. You could try submerging these shavings? Maybe the wood shavings will float but the plastic shavings (depends on the plastic type I suppose) will sink?

[@CNCKitchen]

Good point.

[@onkelnb]

Use a magnet to get rid of the metal particles. I would wrap it in a plastic bag, that makes it easier to clean. And remove the OSB. Use plastic sheets or folded sheet metal instead to avoid the contamination of your shreds with wood particles. Then you can save the finest plastic particles and reuse them to make your own plastic sheets in the oven.

[@andyspoo2]

With all the test prints you do, you probably create more waste than most 3D users. Recycling is the way to go for you.

[@pinesparrow]

perfect job for my cub cadet 70

[@mckidney1]

I wonder if heating the parts will make a difference for the better or worse. It will definitively make them softer with some hot air-flow. while the hot air wont damage the steel, I wonder if layers of will stick to the shredder. Which also brings up the point of some lubrication that could be reused. Hmm over all, this is a great idea. Mainly because the main cost in recycled plastics is sorting them and efficiency goes does like a stone with public services.

[@austinhe11]

You should shred bottle caps and print with the hdpe

[@austinhe11]

Also test the strength

[@MrNathanstenzel]

A few shredder designs use a set of gears to give more shredding power.

[@qvatch]

looks like you might want to add some magnets into that shaker stack to remove metal. You should collab with that guy that keeps printing and 3d scanning the same benchy. Using the same material again and again would be neat.

[@qvatch]

Unless that was also you, in which case, carry on.

[@seb1931]

you should do a vid on the pellet extruder. looks interesting.

[@patrickk118]

I think you can add some gears to reduce the force

[@danielkingery2429]

Taking a hint from bicycles... gearing. You should be able to reduce crank are by puting a large sprocket on the shredder axle and a very small sprocket on the crank axle.

[@billdipperly6435]

I'd consider attaching a wheel with hammers to it set up similar to a bike. Making you able to use more momentum to keep the shredder going.

[@tna2me197]

You should try mounting it to a geared down stationary bike. That would be awesome