3D-Printed Collet Clamp System: Secure Mounting for LEGO Antweight Wheels
Introduction
In combat robotics, wheels are one of the most overlooked but critical components. They translate motor power into movement, absorb impacts from the arena, and can make the difference between control and chaos. Traditional wheel mounting systems often rely on set screws, hubs, or adhesives — all of which can slip or fail under the intense shock loads of a fight.
To solve this, we’ve developed a 3D-printed collet-style wheel system, offering a more reliable, secure, and modular way to attach wheels directly to drive motor shafts.
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What is a Collet System?
A collet works by compressing around a shaft when tightened, evenly distributing clamping force across its surface. This results in higher torque transfer, less chance of slipping, and reduced wear compared to single-point set screws. By adapting this principle into a 3D-printed design, combat robot builders can now enjoy the precision and strength of a collet without expensive machining.
Origins of the Design
The idea for this system didn’t appear in a vacuum. Scott from TurnABot pioneered a similar approach, using a collet-style mechanism for securing wheels. Inspired by his work, we took the foundation of his design and tweaked and adjusted it to better suit our needs.
Our version focuses specifically on LEGO’s 30.4 × 14 mm wheels, integrates a thread-friendly 3D-printable design, and introduces a dual-wrench tightening system for easier installation in tight robot frames. In this way, the design both builds upon and refines Scott’s concept for broader use in combat robotics.
Design Features
- 3D-Printed Precision
- LEGO Wheel Compatibility
- Collet-Style Clamp
- Tooling System
- Combat-Proven Durability
The wheels and collets are printed from durable engineering plastics and require a fine layer height to ensure the threads print cleanly and operate smoothly.
This system is designed specifically for LEGO’s 30.4 × 14 mm wheels, which come in a variety of tread styles. While the wheel selection is limited to this family, these options offer proven durability and grip at the antweight scale.
Instead of relying on friction from a single screw, the collet system grips the motor shaft evenly. This ensures consistent torque transfer even under heavy loads and repeated impacts.
The wheels are tightened using two 3D-printed collet wrenches. One wrench features a slotted design, allowing it to slip over wire harnesses, ESCs, or even the motor itself. This makes tightening possible even in tight, fully wired robot frames.
By removing weak points like loose set screws or stripped hubs, this design helps keep robots mobile even after absorbing big hits.
Advantages Over Press-Fit Hubs
Press-fit hubs are commonly used in smaller combat robots, but they come with major drawbacks:
- Risk of Slipping Off
- Damage to Gearboxes
- Collet Advantage
A press-fit connection relies entirely on friction between the hub and the motor shaft. Under the shock loads of combat, these hubs can easily slip off, leaving a robot stranded.
Smaller N10 and N20 gearmotors, often used at the antweight scale, have fragile gearboxes. Pressing a hub onto the shaft can put dangerous force on the motor assembly, sometimes damaging the gearbox before the robot even hits the arena.
The collet system eliminates both of these issues. Because it applies clamping force evenly around the shaft rather than pressing directly onto it, the risk of gearbox damage is drastically reduced. At the same time, the distributed grip provides far greater holding force than a press-fit, ensuring the wheels stay locked in place fight after fight.
Benefits for Builders
- Stronger and more reliable wheel-to-shaft connection
- Rapid prototyping and replacement through 3D printing
- Reduced risk of shaft or gearbox damage compared to press-fit hubs
- Easy installation and removal with purpose-designed collet wrenches
Conclusion
This 3D-printed collet wheel system offers combat robot builders a new level of reliability and flexibility. Specifically built for LEGO’s 30.4 × 14 mm wheels, it balances accessibility, durability, and ease of use.
