As addition to the filament guide clip for the Ikea LACK tables I added a ball bearing guide to put the PTFE tube through and guide it to the printer head. You bolt it to the bottom side of the Ikea LACK table.
You need two (max) 4mm screws with a flat head to mount the guide in place.
Original Prusa i3 Enclusure - Ikea LACK Table, Filament Guide: https://www.thingiverse.com/thing:3491533
Made this as part of my LACK modification for "Original Prusa i3 MK3 ENCLOSURE -Ikea Lack table - Prusa Research" https://www.thingiverse.com/thing:2864118