Plastic Shredder Cart

I made a plastic Shredder for PP (#5 on the following arrows) and HDPE (#2 on the following arrows)

1. First thing you need is a shredder box available from precious plastics.com
2. Then you need a way to turn it the shaft on the shredder box. I chose a 3 phase 1 hp motor to be controlled by a variable frequency drive (VFD)
3. I used scrap lumber to assemble a platform and hoper for the shredder. (See picture for size)
4. Hinge and plate to mount the motor. I also used scrap metal (1/2" steel plate) and a leftover hinge.

I start by arranging my motor and shredder box to figure out the elevation change. One I had that arranged, I took a picture, uploaded to procreate, and started sketching out the design of my shredder stand.

From there, I started drawing all the pieces out in Sketchup where I tend to go through a lot of iterations as I think about buildability and what material I had lying around. I typically have a stock of pallet lumber that I use, so that's what I based my design on.

To make fabrication and assembly easier, I added rabbets into this design.

Once there is a clear vision of how everything should but cut and fabricated, start cutting wood!

Fabricate lumber:

I had some 2x material previously milled down a bit so it would be straight and easier to work with. I cut the lumber to size (see picture again for reference), then used a track saw to cut kerfs in the wood. Using a hammer, I removed the waste and then cleaned up the joints with a chisel before assembly.

Fabricate the hinge plate:

I used scrap 1/2" steel and drilled out the hinge and motor pattern on my drill press. I simply used 5/16" holes which were oversized to work with 1/4" x 20 thread bolts. This game me enough play since I was using a drill press vs a mill for the fabrication of this plate.

I started by gluing and screwing the 17" long stretches to the Legs first to look like a ladder

After those ladders were put together, it was relatively easy to glue and screw the 11 7/8" stretcher to the ladder assembly.

See attached pictures of how the rabbets worked to help hold everything together.

Bolt the motor and shred box to the cart. Unfortunately, I didn't film or document this part a lot.

For the motor, I mounted the hinge plate to a scrap piece of wood and mounted that to the legs of the cart. I have a clamp adding pressure on the opposite side of the thing to keep tension on the belts for now. Changing the belts is relatively easy as I just have to unclamp the motor, and lift up the motor to take out the belts.

For the shred box, I used some large wood screws to bolt into the lumber.

After the boxes were in place, I adjusted the pulleys to be aligned. I did have to cut out a notch in the lumber to allow the belt to pass through as well. This was done with a hole saw drill and handsaw.

Again... Sorry for the lack of pictures.

I'm an idiot and used this shredder box without a hopper and I would suggest no one else try this. So I made a quick and dirty hopper box to fit on top of the shred box. See rough sketch for how I assembled it.

I added a hopper which is a pure rough prototype. there is a divider in the middle to keep the plastic from moving to the opposite side of the shredder as it tends to fling plastic up if there is not divider.

The current lid is a Polypropylene or PP take out container. That is very temporarily attached but does make a difference as the plastic tends to jump up out of the hopper if that's not there.

I also have a push stick on the side to help push plastic into that nasty shredder assembly. This machine is very intimidating to me so I'm keeping my hand well away from that box!

Plug in (I use 220v quick connect plugs to connect motors to my VFD see link to other video for how I wire motors) the motor to the VFD and start using!

One of the special things I have on this VFD is the option to stop, reverser, and forward the motor. This is helpful for this shredder since I often have to reverse the motor to clear up plastic from getting clogged up.

The motor I'm using is relatively under powered at only about 1.0HP. It's not perfect but it beats cutting up all this plastic into tiny pieces on the bandsaw to shred. Ironically, it even feels a little bit safer.

While having a plastic shredder is a huge improvement from my old set up of cutting everything on a bandsaw, there are still some big improvements I'd like to make.

1. I need to use a larger pulley on the shred box to increase the torque from my motor. I don't want to upgrade to a larger motor or I would need to have 220V power.
2. Belt Guard! To be safer, I need to add a belt guard to this cart so clothes or other rubbish in my shop cant get sucked into the pulley.
3. Small work top. Have a little surface on the top to keep plastic that will be getting shredded.

Overall, I'm excited to have a plastic shredder along with the ability to process a lot more plastic than before.

Thank you for reading and let me know if you have any questions regarding a shredder box, VFDs, motors, etc....

I'm all for helping anyone that is willing to make an attempt at recycling plastic!