Hand and forarm printed in black PLA. I use recessed M3 screws to hold it together. I drill a 3mm hole in the part to be mounted. In the part that it should be mounted to, I first drill a 2.3 mm hole and then I use a 3mm taps to make a thread. It's not easy to make the thread straigth by hand, so I mount it in a drill.The 8mm screws are made from an aluminium rod that I threaded in one end, and made a track in the other end to be able to screw it in.