Introduction: Make a 40$ Cold Juice Press!
Second Prize in the
Invention Challenge 2017
Cold Juice Presses are expensive. The one that I bought does not even work propperly. So I decided to come up with something better, simpler and most of all cheaper!
I belive that we as a society can become healthier by juicing. Not just because of the vitamins and the minerals, but even just because a glass of juice could replace a poptart, a cheseburger or a can of coke.
Materials you need:
- 40mm plywood. You can glue together multiple sheets with woodglue.
- durable indoor paint
- 4 ton hydraulic jack
- 10mm or 3/8" threaded rod
- A flange that fits your hydraulic jack.
- Instamorph (plastic that melts in water)
- stainless steel sheet
- primer spray
- wood glue
- a counter sink bit
- an orbital sander
- thread cutters
Super Simple Safety Advice:
- Keep your hands as far away as possible from anything that moves.
- Wear safety shoes.
- Wear safety glasses.
Step 1: Make the Juice Tray
Making the tray was easier than I thought. If in doubt, apply more force : )
The sheet metal should be less than 1.5mm thick. You can bend it with a metal break, but since most people don´t have one at home, I used pieces of plywood as guides. The basic idea is to clamp everything down that you want to stay flat so the bends only form where you wan to.
Start with the sides, than do the back and finish with the funnel at the front. At some point you need to trim the sheet metal at the funnel. Use an angle grinder with a cutoff disk. You don´t need to get a stainless steel disk for that. Any cuttoff disk will do.
Of course if you have a welder you can do this without the overlapping corners.
Step 2: Cut the Wood!
You need 4 pieces of plywood. The rough sizes are below, but you should choose them according to the juice tray you already made. The thickness of plywood should be about 40mm. Thicker is better. To thin and it will just break. I did some FEA analysis, and it came to about 38mm, but this value is only a rough guide.
- 2x plates for the top and bottom. (300mm x 300mm x about 40mm)
- 1x plate for the tray holder. (220mm x 220mm x 220mm x about 40mm)
- 1x block for the plunger that does into the metal tray. (160mm x160mm x about 40mm) This depends on your tray dimensions.
The good thing is that precision is not important!
Step 3: Finish the Top and Bottom Plates.
Drill out the holes to match your threaded rods. I used 10mm threaded rods which are required for a 5 ton press.
You can add a nice roundover to the edges with a disk sander or a jigsaw and an orbital sander. I made mine match the diameter of the washers that I was going to use later. Washers are esential!
Give the wood a light sanding up to 180 grit to prepare them for paint.
Step 4: Cut the Threaded Rod.
You can use a hacksaw or an angle grinder to cut the threaded rod. It should be at least 10mm for a 5 ton press. A flapdisk can be used to smooth out the ends.
Step 5: Make the Plunger
The plunger pushes into the metal tray and needs to take a lot of pressure. I made mine from the same plywood and used some scraps glues together for this. The force is only compressive perpendicular to the glue line, so glue is all we need. The dimensions should be chosen so it fits into the metal tray with about 2 fingers of space to all sides.
I recommend using a couple of screws for the glue up. The wood slides on the wet glue and makes a mess.
You can give the bottom edge a round over. That makes it easier to remove the plastic plate later on.
Step 6: Finish the Tray Holder!
The tray holder is basically just a piece of thick plywood. You can add little rails to the sides so the juice tray does not slide around.
I gave my tray holder some chamfers around the edges. This makes it appear lighter. I guess it actually is lighter.
The tray holder needs to be reasonable thick because it transfers all the force from the hydraulic jack. I got one of those hand rail flanges to attach the juicer to the hydraulic jack. A thick piece of steel fromt the hardwarestore transfers the pressure from the hydraulic jack.
Step 7: Paint!
Did I mention this is my favourite part?
The goal to a good paint job is good paint and a clean environment. I clean my entire shop and cover the entire area with plastic, so no dust can be blown up.
- Start with a wood primer and do a light sanding after the first coat. This removes the wood fibres that rise up on the first coat. This happens with any paint, even with plain water.
- Add a thin coat of paint and let it dry fully.
- Sand the first coat of paint lightly with 120 grit sandpaper. Clean off the dust thoroughly!
- Apply another coat of paint.
- Repeat until you like the finish.
I also painted the hydraulic jack green. Just because I could.
Step 8: Make a Plastic Plate for Food Contact.
The only thing that should come into contact with the juice should be food safe. Stainless steel is fine for the tray and at the top, I added a plastic plate. I ordered a cheap HDPE cutting board and cut it to size. HDPE can be cut extremely easily with any woodworking tool.
(The leftovers can be great rails for a cross cut sled.)
I used magnets and dowels for allignment. Its very difficult to glue anything to HDPE, so I screwd counter sunk screws into the plastic and glued the magnets into the wooden plunger that we made earlier. This works very well! Two dowels is all you need for allignment. There won´t be a lot of force acting on them.
Step 9: Pimp the Hydraulic Jack!
These hydraulic jacks are great, but the handle and the pressure release handle are not very conveniant. We can fix that!
There is this really cool plastic that you can melt in boiling water. It is quite strong, not brittle, and you can re-melt it over and over again. I used this numerous times and it is often much easier and better than fabricating something out of wood or metal. I used it to make a little level for the pressure release knob on the hydraulic jack. This lever is used very frequently and should be easy to grab without having to use tools.
I joined both parts of the handle with screws and tapped holes. I also attached the handle permanently to the hydraulic jack.
Step 10: Final Assembly!
Now that all the parts are build you just need to assemble it. This should be straight forward by now. Well done!
A few tips:
- Use nylock nuts!
- Use one of those locking pliers to hold onto the threaded rod.
- Use a cordless drill. Why make life dificult? Thats what kids are for.
- Pre drill any screws that you add to the plywood.
Step 11: Admire Your Work.
You build a beautiful cold juice press that will provide tons of vitamins and minerals. Give yourself a pat on the back!
Step 12: Juice!
This is what we all have been waiting for. The healthiest thing you can drink, made from scratch with your own hands.
- Dice your fruits using a food processor. Soft fruits like cucumbers, oranges and watermellon can be juiced straight away, just remove the shells.
- Place a batch of chopped fruits and vegetables into a chese cloth.
- Place the chese cloth in the press and start juicing.
- The juice will flow out of the juicer very easily.
GiovannyP2 made it!
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