The filament guide is composed of two sections that are designed to be assembled together. The purpose of this assembly is to create a channel through which a filament or PTFE tube can pass. This channel is specifically designed to facilitate the movement of the filament or PTFE tube through a wall or shelf. It is important to note that the filament or PTFE tube can pass through the guide without any restrictions. 
 

In order to proceed with the drilling, it is necessary to utilize a hole saw with a diameter of 32 mm (1 1/4 inches). Prior to drilling, it is imperative to ensure that the printer is in its final position and that the necessary measurements have been taken to ensure the hole's central positioning relative to the extruder and the filament or tube in motion.

The hole's dimensions approximate 5.7 mm, allowing for the reduction of the parts' scale to accommodate a thinner wall while maintaining the necessary space for the filament (1.75 mm) or the PTFE tube (4 mm) to pass through. If reduced to 80% of its original whole size, it will still be able to accommodate a PTFE tube and be used for a 15 mm (5/8") wall. It is possible to shrink it further for filament passage only, up to a certain limit which should be tested, as this could lead to problems with the threads for screwing. The same ratio can be used with the original design that mesure 32 mm in height to get it to use on a 25 mm (1") wall. You also can change only the height to keep the hole dimension.