In Pursuit of Uncompromising Control: Building a Combat-Ready Custom Leverless Controller with the Bambu Lab P2S

The fatal flaw of 3D printed parts (PLA) is the durability of screw holes. If you screw tapping screws directly into the plastic, the threads will strip after just a few openings and closings. For a custom arcade stick that assumes frequent maintenance, this can be a fatal blow. Therefore, for this unit, I adopted heat-set brass threaded inserts to join the case and the bottom plate.

Here's a quick tip: for a 4.1mm diameter nut, intentionally design a tight 3.8mm pilot hole. By pressing it in while applying heat with a soldering iron, the surrounding PLA melts and bites firmly into the nut, creating a rock-solid thread. Furthermore, to connect the two-part case, I combined temporary screw fastening with clamping from the bottom plate, achieving a seamless, rattle-free unity.

Another obsession was the interchangeable top plate design gimmick. I printed a separate 1mm thin cover and incorporated a structure that snaps into place using neodymium magnets. By embedding magnets in the case with epoxy adhesive and installing iron screws in the cover, the top plate could be attached and detached without tools. ...Or so it was supposed to be, but this gimmick would later lead to an unexpected tragedy.

Installing buttons is the best part of DIY, but with a 3D printed case, precision is everything. This time, prioritizing cost performance, I used Seimitsu 24mm snap-in buttons. After obsessively repeating test prints, I succeeded in finding the perfect clearance for a satisfying snap fit. There is absolutely no shifting during keystrokes.

On the other hand, the external connection interface gave me a lot of trouble. As a modern gaming device, USB Type-C integration is a must. So I incorporated a panel-mount Type-A to Type-C adapter cable, but this part is surprisingly expensive and options on the market are scarce. It left me with a lingering anxiety about future parts supply (handling discontinued products). Ironically, through DIY, I came to understand why commercial products use proprietary connectors.

Then, in the final stages of assembly, a fatal design flaw was discovered. I made the button holes on the previously mentioned '1mm thin interchangeable top cover' the exact same size as those on the base top plate. As a result, the rims of the buttons firmly held the top cover in place, leading to a self-defeating situation where 'the cover cannot be swapped without removing all the buttons.' It was a bitter mistake that completely killed the convenience of the magnetic mount. This is something I absolutely must fix in the next model.

Organizing the wiring after all parts are housed. If you cut corners here, you'll go through hell during future maintenance. With cables crossing from over 10 buttons, the benefit of aggregating the GND to a custom terminal really paid off here. Because I could clearly separate the routing of signal wires and GND wires, I reduced the risk of pinching cables when closing the bottom plate to zero.

Furthermore, just as important as rigidity for actual combat is the 'anti-slip treatment of the main body'. When performing intense inputs, even the heaviest arcade stick will slide around on a desk. Simply sticking on commercial rubber feet with double-sided tape guarantees they will shift and peel off over long play sessions. So this time, I took the approach of placing multiple small dimples, a few millimeters in diameter, during the bottom plate design phase.

I poured a commercial liquid anti-slip coating, which turns rubbery when dry, into these dimples and let it cure. The results are excellent. It formed powerful grip points completely integrated with the bottom plate, providing overwhelming stability that doesn't budge an inch even during intense play right on the verge of desk-slamming. I also custom-made blind caps to plug unused button holes, elevating the overall polish of the product.