This design is similar to my other RC10 battery box designs. The only difference is that this version is 5mm longer to accommodate longer battery packs. I could not extend the length any further without interfering with the stock servo mounts.

Use a 4-40 tap to thread the mounting holes on top and bottom.

You may also want to use my top/strap. It has a modified keyhole to accommodate PLA material being less flexible than the original nylon.

Creality

Ender 3 Pro

No

No

.12mm

100%

When tapping the mounting holes, clean debris frequently to avoid clogging the tap and fouling the holes.