DIY Easy 3D Printed Vertical Spinner Combat Robot - Build Your Own!

Building a combat robot is more than a weekend project. It’s a mix of engineering, design, and a bit of chaos that teaches you how real machines behave when they’re pushed to their limits. You learn how materials fail, how power moves through a drivetrain, and how small design choices decide whether your robot survives a hit or folds in seconds.

This guide walks through how I built my beetleweight combat robot. If you’re curious about turning ideas into tough, reliable hardware, or you want a hands-on way to grow your skills, this is a solid place to start.

And in my opinion, combat robotics is the perfect place to start even if you are completely new to electronics - because once you understand the electronics, you can build almost unlimited configurations of a combat robot (note: all of the images above use similar electronic configurations: two drive motors and one weapon motor/servo)!

Lastly, the beauty of this project is the ease-of-entry. I use a lot of 3D printed parts, meaning you don't need to have access to a CNC mill or a laser cutter. I also use similar bearings (608 bearings, found in skateboards) throughout the entire designs, and the design only uses m3 and m5 nuts & bolts. Nothing proprietary, all made with love in Fusion!

*Quick Disclaimer: WARNING: Combat robotics is extremely dangerous. Serious injury or death can result. Build and operate at your own risk. Read the full disclaimer below.)

Let’s get into it!

some product links have affiliate links which support my work!

Materials

1. 3D Printer: preferably having a build area of greater than 250x220x220 (x,y,z)
2. I used a Prusa i3 Mk3s+
3. 3D Printing Filament
4. Tough Filament: PETG OR PCTG OR PLA+, etc
5. Flexible Filament: TPU OR TPE, etc
6. Electronics (this is where you have flexibility!)
7. 1x 2836 brushless motor (weapon motor)
8. 1x unidirectional ESC (electronic speed controller for weapon)
9. 2x bidirectional ESC (electronic speed controller for drive)
10. 1x receiver and transmitter (this is how you remotely control the robot!)
11. (Optional) basic LED light
12. Soldering iron (you may not need this, but recommended!)
13. Hardware
14. m3 nut & screw kit
15. this should include the hex key!
16. m5 nut & screw kit
17. this should include the hex key!
18. 608 Bearings
19. aka skateboard bearings
20. 5x13x4mm Flange Bearings
21. commonly found in Ender 3 3D Printers
22. (Optional) Metal parts
23. if you are fortunate enough to have access to a CNC mill or laser cutter, you may want to create some parts (armor, weapon disks, etc) out of metal. For the sake of this intractable, I stick to solely 3D printed parts! And don't worry - 3D printed parts can also pack a punch!

Warning: This project requires good judgment - you will be interacting with potentially dangerous objects. Do not spin up the robot near yourself.

Safety

1. Safety glasses (or safety squints haha)
2. A safe place to test your robot
3. maybe an abandoned parking lot
4. maybe a proper transparent cage
5. maybe an empty room

Tools

The assembly is relatively simple, needing minimal tools, but having access to these may make your life easier in a pinch:

1. sand paper - in case things don't fit together
2. driver/drill - to enlarge holes
3. adjustable wrench - to tighten bolts
4. multimeter - to ensure proper electricity flow (and to prevent short circuits)
5. strong stack of small magnets
6. these are perfect for guiding screws into hard-to-reach slots and retrieving nuts!
7. set of quality (and long) allen keys.
8. this will make your life a lot easier!

Miscellaneous Requirements

1. patience: this project will take time
2. ability to problem-solve: don't hesitate to search things up (Youtube will be your friend!)

DISCLAIMER

This guide is provided for informational and educational purposes only. Building, operating, or participating in combat robotics involves significant risks of serious injury, death, property damage, and legal liability.

By following this guide or building a combat robot, you acknowledge and agree to the following:

1. High Risk Activity Combat robots can cause severe injury or death due to high-speed impacts, flying debris, sharp edges, powerful motors, high-voltage electrical systems, hydraulic/pneumatic components, and potential for fire or explosion.
2. Personal Responsibility You assume full responsibility for your own safety and the safety of others. You are solely responsible for determining whether you have the necessary skills, knowledge, equipment, and judgment to safely build and operate a combat robot.
3. Compliance with Laws It is your responsibility to comply with all applicable local, state, national, and international laws, including but not limited to weapon laws, safety regulations, noise ordinances, event-specific rules, and insurance requirements.
4. No Warranty or Guarantee The author(s) of this guide make no warranties, express or implied, regarding the accuracy, completeness, safety, or suitability of the information provided. Use at your own risk.
5. Not Professional Advice This is not professional engineering, electrical, mechanical, or legal advice. Consult qualified professionals (engineers, electricians, lawyers, etc.) as needed before building or operating a combat robot.
6. Indemnification You agree to indemnify, defend, and hold harmless the author(s), contributors, and any affiliated individuals or organizations from any claims, damages, losses, liabilities, costs, or expenses (including legal fees) arising from your use of this guide or your combat robot.
7. Event Rules Most combat robot competitions have strict rules regarding design, weight, weapon types, power systems, and safety. You must follow the rules of any event you enter. This guide is not affiliated with any specific event or organization.

If you are not prepared to accept full responsibility for all risks involved, do not build or operate a combat robot.

(sorry, I just don't want to get sued, but seriously: BE SAFE!!!)

Let's get the hard part done, shall we? As long as your electronics are working, the rest of the build will go smoothly!

Warning:

If you have no prior experience with electronics, I'd recommend familiarizing yourself with safety, especially SHORT CIRCUITS. The 12V LIPO battery may have short circuit prevention, but it can be very dangerous regardless (possible sparking/explosion/fire)!!! DO NOT SHORT CIRCUIT THE BATTERY!

1. I'd recommend watching a YT video, but basically if you connect the two terminals of a DC battery (the positive and the ground) together directly, without any components using the electricity, you are short circuiting

Please refer to the wiring diagram & the YT videos if you are at all confused (it is quite hard to describe electronic schematics in words).

First of all, gather all of your supplies:

1. 2836 brushless motor (weapon motor)
2. 1x unidirectional ESC (electronic speed controller for weapon)
3. 2x bidirectional ESC (electronic speed controller for drive)
4. 1x receiver and transmitter (this is how you remotely control the car)
5. (Optional) basic LED light
6. Soldering iron (you may not need this, but recommended!)

Be sure to bind the receiver to the transmitter using the bind-clip. (If you're having trouble, use a Youtube tutorial!)

It helps to visualize how the electricity flows through the circuit. (refer to the image of wiring or the video tutorials)

1. The electricity will start in the red (positive terminal) wire of the battery, and that red wire will need to travel to the red wires of each ESCs (that means you'll have to splice a total of 4 wires together)
2. The electricity will need to flow back to the negative terminal to complete the circuit

The 3D model can be found here: https://www.printables.com/model/1468308-piggy-3lb-combat-robot-almost-fully-3d-printed-v1

Use the 3mf file for easy printing!

3D Printing parts is pretty straightforward: just 3D print them with the right settings and materials.

I don't want to make this complicated for the beginners, but if you have experience, you can pick your own settings.

There are 3 categories of printed parts with their respective print settings:

1. load-bearing/impacting parts
2. use the rigid/tough filament with high infill percentage (30+%) and high perimeters (3+)
3. flexible parts
4. use the flexible filament with moderate infill percentage (8-15%) and moderate perimeters (2)
5. maintains flexibility
6. non-crucial parts
7. use the rigid/tough filament with moderate infill percentage (8-15+%) and moderate perimeters (2)

I will label each of the categories, but here is a comprehensive list below:

Flexible Parts:

1. Back Wheels
2. Front Wheels
3. Weapon Hub

Load-bearing/impacting

1. Weapon Blades
2. Drive Pinions
3. Back Wheel Hub

Non-load-bearing (you can print these at a higher-strength, but this gives you the option)

1. Drive-Train Base
2. Chassis (main base)
3. Belt Tensioner Components

I will attempt to group these in the Slicer 3mfs! However, it is a good rule of thumb to print all parts with moderate strength - when you encounter a mechanical failure (weak point in the design), consider reprinting the part or upgrading it.

Now the fun part! This step is the most satisfying, since you get to see your robot come to life!

Note that this applies to my own robot design, so if you made any modifications, you won't follow these guidelines step-by-step!

PLEASE REFER TO THE 3D CAD MODELS IF YOU ARE CONFUSED!

Let's start with the weapon:

Drisk Weapon Assembly

So the drisk is a drum and 2 disks. Almost like a sandwich.

To assemble:

1. Take the TPU hub
2. Insert 608 Bearings on both sides, in their respective slots
3. Insert m5x40 hex standoffs into each of the corresponding slots (note: you can also use two m5x20 hex standoffs if you don't have m5x40)
4. Slide in the weapon offsets, the weapon blade and the spacer
5. Tighten down the 6 m5 screws on each side
6. Repeat for the other side

Drivetrain Assembly

So now we're onto the drivetrain. Simply repeat the steps below for both sides

1. Attach the pinion gear onto the 2306.5 motor. Use the m5 bolt (with loctite) to secure it.
2. Press 608 bearings into the wheel hubs
3. Attach the brushless motor to the drivetrain base using m3 screws, keeping the gears (of the motor and wheel) aligned
4. while you do this, you can slide in the bearing onto the shaft
5. Attach the front wheel & its bearing into the shaft
6. Assemble the belt tensioner using m5 screws
7. Repeat steps 1-5 for both sides

Chassis Assembly

1. Take the weapon belt (TPU) and loop it over the weapon
2. Use the m8 bolt and stick that through the 608 bearings of the drisk weapon
3. Grab the 2836 BLDC motor and tighten it down to the chassis, embedding the nuts first
4. The belt should be able to loop over both the drisk weapon and the weapon motor
5. Assembly the weapon belt tensioner using m3 screws and the flange bearings
6. Attach the drivetrain to the chassis by using m3 screws both in the front and in the back (insert m3 nuts!)

Electronics Integration

1. At the moment, the housing for the electronics is rather unorganized, so everything is shoved inside & the top cover is attached. You can use the Fusion file to create custom housings, depending on your components

I know that those instructions were rather vague and possibly hard to follow along. I will be updating this Instructable in the future with step-by-step follow along videos to assemble my combat robot. However, it is a lot easier to assemble something if you are the creator of the design, so I strongly encourage you to take the knowledge from this Instructable to create your own combat robot design using Autodesk Fusion!

Ok. Pretty much the last step here. Now, you will just need to set up your receiver and transmitter to control the motors properly.

Youtube, yet again, will be your friend here! There are some really good channels out there, especially: Team Panic and Just 'Cuz Robotics.

Remember:

the transmitter/receiver model I used was: Flysky fIA6

the ESCs were the Defiant bi-directional ESCs from RC Electric parts

Use the respective websites (find your specific product's website) to figure out how to bind/set up the ESCs and Receivers!

This step took myself a good bit of time, so be patient!

Thank you for reading this Instructable! I hope you got something out of it! Cheers!