Micro:bit case

Micro:bit caseThe front and back sides are connected using a piece of 1.75mm filament. I do it by connecting the front and back sides of the empty case, then using a power drill with a 1.8-1.9 mm drill, I clean the tunnel for the filament on both sides.... I connect the halves on one side with filament and then insert the Microbit, close the case and secure it with the second piece of filament. But if you cut it flat, nothing happens, you just push it out with a piece of filament....Micro:bit ca