3D Printed Excavator

Want a fun toy for the little ones? Also teach them how hydraulics work! This was a fun little project for me, i wanted to make something for my little nephew to play with but also something to teach him how real excavators work and what better way than the old tried and tested syringe and pipe hydraulic system? With a few modifications.

All needed files for printing is attached in the last step! :P Modeled in Autodesk Fusion 360.

Well firstly you will need a 3D printer and some filament!

Most of the parts will need to be printed and it does take some time.

Parts to buy:

1. 6 Syringes (10ml)
2. Clear tubing
3. M6 threaded rod
4. 8 M6 nuts
5. 8 M6 washers
6. 8 M10 washers
7. Various sizes M3 screws, if they are too long you can always cut them so the longer the better.
8. Some yellow and black spray paint (Yellow is not applicable if you have yellow filament)
9. Some thin copper wire
10. Zip ties (I got yellow to keep with the yellow theme)
11. Brush cutter wire or filament (3mm or the closest you can get to it)
12. Some superglue (Make sure it's plastic friendly or you might lose all hope for life if it melts the plastic)
13. Some sanding paper, roughness is not really important!
14. Water/oil
15. Food colouring if you want to

Tools you need:

1. Hairdryer (Used for a cool trick i learned a few months ago)
2. Soldering iron
3. Some spanners
4. Any saw
5. Some pliers
6. Screwdrivers
7. Knife
8. Lastly a 3d printer!!! NB!!!

You will also need some time to get everything printed and painted! Assembly is a quick process. :)

Firstly you will need to print everything. Most of the parts will use support material just to make sure the parts come out looking good! I printed the main body first because it's the biggest and longest part to print, took about 14 hours to and used 500g of filament so be sure you have enough to print this. All the other parts are small and easy to print so they can be done in any order. I printed everything then painted everything before i started assembly, this just gave good coverage and didn't leave any crevasses unpainted. When everything is printed and painted you can start with the assembly!

You will need to superglue the roof on the excavator. I printed the body without the roof to avoid unnecessary support material and waste filament.

The tracks are built up from smaller track parts. You will need 66 of these parts, 33 per track.

You will need to cut the copper wire or any thin wire to size and bend in an L-shape and these are used to connect these tracks to each other. Keep building and building until you have the 2 strips as shown in the picture above! Don't close the loop yet.

We start with the lower part of the carriage. You will need the lower carriage part the threaded rod and all the bolts and washers. The track wheels.

Thread 2 bolts to the center of each threaded rod.

Insert them in the 2 holes with one 6M washer and 2 M10 washers as shown.

You can then slide on the track wheel and this will also slide into the holes on the carriage.

One 6M washer on the outside and then one more bolt.

Tighten everything , not over tight just enough to keep everything together and allow the wheels to still turn.

You will need the hairdryer (Finally), the upper carriage and the large gear wheel with the 2 pins.

Now you can find out what the hairdryer is for. Using the hairdryer you heat up at least 2 of the pins on the carriage, this heat will make them soft again and you can easily bend them a bit and put on the upper carriage piece. Bend them back and just let them cool down.

Secondly you can take the bigger gear with the pins and just insert them on the upper side of the lower carriage as shown.

Now you will need the turning screw and the small gear plus some superglue and of course the main body.

Slide the turning screw through the main body. Put some superglue on the small gear and then screw it into the turning screw from the bottom. Give it a few minutes to dry (Make some coffee or crack open a beer).

Next we finally get to mate the main body and the carriage. Take the main body and just screw it on to the carriage you just built, using some 3mm screws (max 25mm long).

You now have something that resembles a thing you know.

You need 3 of your syringes and 3 of the syringe tips. The backs differ in length so you need to print the 3 different backs.

Cut off the back of the syringe with the saw.

Then just put on all the tips and backs.

You will need the Brush cutter wire, soldering iron, the 2 arms of the excavator and the bucket.

Assemble the arm as shown in the picture. These pivot points will use the brush cutter wire, insert a cut piece through the pivot then you use the soldering iron to melt both points of the wire to step it from falling out.

Now take 2 of the syringes , one with a short back and one with the long back. Connect the syringes as shown in the picture , the one with the short back is used for the bucket and the long back is used for the arm connected to the bucket. Screw them in with the syringe tip to the top.

Now using the same process as the previous steps just connect the excavator arm to the body using brush cutter wire (Melt the tips) at the hinge and bolt the syringe onto the body and arm using 3mm bolts.

You will need your clear tubing and your zip ties and the 3 syringes that are left.

Firstly you will need a piece of wire (The copper wire will work) thread this through the hole just behind the excavator arm(pictured above) use this to pull the tube through this hole.

Now you connect the pieces of pipe to the 3 syringes that are left and secure that with the zip tie.

Thread the pipe through the excavator, each pipe to another syringe, the orientation doesn't really matter(which syringe pushes which part of the arm).

Before you secure the pipes on the syringes on the arm of the excavator go to the next step.

Now you need to fill everything up.(I removed the carriage here because that just made it much easier to do and photograph)

I used 3 different colours in just tap water, so you can see what syringe is activated by what other syringe and you can also see how the fluid moves(Educational as hell).

But you can also substitute the water for cooking oil or any other liquid.

Make your small glasses of water and you need to suck up the fluid with the syringes in the body(Keep the pipe on so you fill that too).

Fill the syringes to a point where you can't move the parts of the excavator more than they should.

This will take a few trial and errors to get right but just keep going.!

Now you need the strips of tracks you built. Roll this over the wheels on each side and complete the loop, put a copper wire in to keep it in place.

Vuala! The excavator is basically done.

Now you can add smaller details to your liking. I made the cabin and the tracks black.

It should now be finished and working!

Attached are all files needed for the project! Everything was designed and drawn on Autodesk Fusion 360.

If anything is amiss please leave a comment so I can get it uploaded.