Many cheap CNC routers are based on 20mm square extruded aluminium frames, with slots and a hole running along them to attach fixtures. Often the four pieces of the frame at the bottom lie directly on the underlying surface, with no supports at the corners. That can be a problem as routing can cause a fair bit of vibration that can be transmitted straight into your work surface. If left unchecked, that can lead to annoying noise as the work surface and adjoined walls and floors vibrate with it. So, I designed this simple foot that can be slotted into the end of a 20mm extrusion that lifts it off the surface below, and which you can also use to add a small rubber or felt pad, further reducing noise and vibration. To get the STL files for 3D printing just click here.