This is an updated Y-Pulley holder for a HICTOP 3DP-11 (a prusa clone). The original was made from laser cut acrylic and simply wrapped a bearing. The belt would rub and squeek. So I designed a bracket that would hold a GT2 Aluminum Timing Belt Idler Pulley. The pulley rides on a bearing and the fins in the side of the pulley keep the belt from rubbing. And now I can hear myself think while the printer is going.
Print this with top of the installed part down in contact with the print bed. I put a champfer on the bottom of the side that sits againt the 2020 extrusion. This is so it will print without support. All hardware to connect this is M5 socked head stainless steel screws. You need an M5x30 with a nylock nut to hold the idler pulley. And I used two M5x16 to connect to the 2020 extrusion. The M5x16's are too long. So I added a washer and a lock washer at the head of the socket head screw to keep them from bottoming out. It worked very well for me I was concerned that the idler pulley had a much smaller diameter than the bearing that came with the HICTOP. But after installing it there was plenty of clearance for the belt.