Picture of Hydraulic Arm
This hydraulic arm was a homework for my daughter's school. The idea was to create a toy from recycled materials. Hope you enjoy.


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Step 1: Materials

- Pieces of cardboard
- 8 syringes
- 1,5 meter hose (aquarium pump)
- 15  Plastic clamps
- 2 screws with 3 washers and 4 nuts
- 1 piece of wire (clothespin)
- 1 wooden stick
- Water, paint, glue, knife, ruler, etc..

Step 2: Planning and Cutting

Picture of Planning and Cutting
We made two drawings of what would be the arm and joints. This allowed us to readily quantify the material being used.

After choosing the model that we would use, cut the pieces (not much criterion measurements) as shown in picture.

Step 3: Cutting and Mounting Arm

Picture of Cutting and Mounting Arm

Step 4: Cutting and Mounting Claw

Picture of Cutting and Mounting Claw
The gripper is designed to move just one piece. It was more simple.
The "finger" was pasted fixed and mobile was seated on a shaft made with a piece of wooden stick that had a piece of cardboard cut in a circle glued on top so as not to leave the place.

Step 5: Cutting and Mounting Base

Picture of Cutting and Mounting Base
The base was made from two pieces of cardboard in order to support arm and accommodate syringes in the same set.

The movable part has two holes:

- One in the center (to be able to rotate the base)

- The other end (to link the syringe and allow movement)

The syringe was attached to another piece of cardboard to keep the same level of mobile base.

After verifying the limits of movement, we fix the syringe with the clamps.

Step 6: Putting it all together

Picture of Putting it all together
After created the arm, claw and base pieces together to test out the movements and check if everything is working properly. Once assembled, we found that the syringe clamp was not well positioned. We cut a piece of cardboard to attach the syringe to another position, as shown in figure.

Step 7: Painting

Picture of Painting
After completing the check and corrected minor errors, disassembled the arm as far as giving and paint. After the paint dries, put together definitely.
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makershaker052 months ago

I favorited this as soon as I saw it. I really love the idea, and the vibrant colors! Thank you for the time you spent making this instructable, I really enjoyed it and was educated in hydraulics through it.

PeckLauros (author)  makershaker052 months ago


jamie.parr.1818 hours ago

where did you buy the syringes?

PeckLauros (author)  jamie.parr.183 hours ago

I bought at a pharmacy.

akshaygill18 days ago

this is awesome.. I really loved it

PeckLauros (author)  akshaygill14 days ago


makershaker052 months ago

I do not need the demensions to each part but just out of curiosity, (hope I don't get killed like the cat), what is the size of the whole project put together? I don't even need exact numbers an estimation would even be fine.

Dullz5 months ago
Made a few changes but got the main idea from you, thanks! ;)
PeckLauros (author)  Dullz5 months ago


Dullz5 months ago
Wow thanks a lot, this design was AWESOME. Look at my profile picture, I'm finally finished with it.
Dullz5 months ago
Busy making it and it's really FUN!!!
PeckLauros (author)  Dullz5 months ago

Also enjoyed myself.

gholam5 months ago
nice design
PeckLauros (author)  gholam5 months ago


Dullz5 months ago
PeckLauros (author)  Dullz5 months ago


Danny roxxx7 months ago
As simple as you and your brains rock
hashwanth10 months ago
i want the measurements of everything !!! please
PeckLauros (author)  hashwanth10 months ago
Hi! If I find the claw, I will put measures.
wow extraordinary
PeckLauros (author)  K S VigNesh1 year ago
3366carlos1 year ago
5 jalapenos!!
PeckLauros (author)  3366carlos1 year ago
vkz.soni1 year ago
plz can i know the size of the syringes used
PeckLauros (author)  vkz.soni1 year ago
Hi Sorry for the delay in responding. In this project, I used 3ml syringes. I do not know the size because I'm not home. As soon as I can, will check the size of them. Although size does not matter much. It depends on the size you'll want to build your mechanical arm.
mangomango1 year ago
Absolutely brilliant! I never would have imagined using syringes like that
PeckLauros (author)  mangomango1 year ago
Lorddrake1 year ago
5 stars :)
PeckLauros (author)  Lorddrake1 year ago
Thanks !
wilgubeast1 year ago
So awesome! This would make an awesome classroom kit if one had access to a laser cutter.
PeckLauros (author)  wilgubeast1 year ago
I agree!
nhormell1 year ago
last year i did one of these for my science fair project
i made it out of card board and covered it in duct tape
it got first place i got a trophy
PeckLauros (author)  nhormell1 year ago
Well done! "Keep Walking"
vandalex1 year ago
Pretty wicked dude! I'd love to see it in action. Wish I could've came up with that kinda stuff back in school for science projects.
PeckLauros (author)  vandalex1 year ago
video ok
PeckLauros (author)  vandalex1 year ago
Children always like this kind of project too. So I decided to put here.
Kiteman1 year ago
That is awesome - Grade A, I hope?
PeckLauros (author)  Kiteman1 year ago
(Oh, and could we see a video?)
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