40mm to 25mm fan adapter for ROBO 3D

This adapter is for Robo3D R1 Plus 3D printer. I use this adapter to replace the stock 25mm extruder fan with a very quiet fan. I tried several 25mm fan and found most of them poorly made. So I design this adapter so that it will fit 40mm fan. After replacing the fan, the temperature is stable.

Use the original screws to mount the adapter to the original screw holes. I use 15mm flat head screw and cap to mount the 40mm fan (the bottom two holes) and about 12mm wood screw to secure the top two