Now we need to solder the 2x20-pin male headers onto the GPIO of the Raspberry Pi. To make this easier, I used a 3D printed jig to hold the headers on the Pi. This helps keep the header nice and straight while we solder each pin. Once the male headers are fixed in place, we can secure the jig to a panavise. You’ll have to solder each pin from the bottom of the Pi.
We'll have to shorten the header pins so the plastic holder bit is flush with the female headers on the Joy Bonnet. If we install the Raspberry Pi to the Joy Bonnet as is, it'll be too thick to fit into the case. So, this isn't optional. I used a pair of flush diagonal cutters to cut the pins in half. I just had to be careful not to cut them too short and try to keep them all about the same height.
With our headers now soldered and trimmed, we can work on mounting the Pi to the case. Place the Raspberry Pi into the bottom half of the case. Then, position the board so the mounting holes line up with the ones in the standoffs. Now we'll insert and fasten M2.5 x 5mm machine screws into each mounting hole. I recommend using a hand screw driver and not a drill. The drill may be overbearing and split the part. Fasten slowly, the holes are a bit small to compensate for tapping threads into them. Ensure the screw is going down straight and not at an angle.
Mount Joy Bonnet to Case
Next, we can work on securing the Joy Bonnet to the top half of the case. First, placed and insert all of the wooden buttons into the cutouts on the top half of the case. Now we can grab the Joy Bonnet and laying it face down. Line up the mounting holes with the standoffs and fasten machine screws.
And with our two halves assembled, we can bring them together to finish this project. We just need to make sure the male header pins from Raspberry PI are going straight into the female headers on the Joy Bonnet. Firmly press the two halves together to close it shut. And that's all folks!