A self-centering alignment tool for boards, squared timber, etc. It allows you to perfectly mark the center of any suitable workpiece.
Cut the two pieces out
Glue it together and insert the two M4 nuts
Screw the screws into the nuts from the other side. Done
Push the tool with the screws flush against your workpiece, as shown in image 1. Then, insert a pencil into the top hole and draw an even line on the workpiece by moving the tool from top to bottom while ensuring that the screws remain in constant contact with the workpiece.