MZ76 v2 extruder (MK3S/MK2.5S) with fan heat set inserts

I'm a big fan of MarcoZ76's FDM-printable redesign of the Bondtech upgrade for the Prusa MK3s. After taking apart my extruder for maintenance a few times, though, I noticed the screw holes for the extruder fan were getting loose. My fan wasn't fitting as snuggly and was beginning to rattle a bit. I know some people go to great lengths to avoid having to use heat-set inserts, but I think they're a pretty easy way to ensure things stay fastened well over time and through multiple rounds of reassembly. I updated each of the screw holes for the extruder fan, as well as all of the existing holes for Bondtech heat-set inserts, to accommodate J&J Products M3 threaded inserts (5.7mm length). I haven't ever had issues with the Bondtech inserts, but these ones from J&J are thicker and I've had really good luck with them in other applications. The holes for the inserts have a 4.2mm diameter at the surface and an 8° taper to accommodate the tapered shape of the inserts and to help with inserting them straight.

I recommend using the right tool for the job when inserting these threaded inserts. A standard soldering-iron tip will work, but using an actual heat-set insert tip will help with straight and flush installation.

I printed mine using ASA and PrusaSlicer's built-in Prusament ASA profile. For infill, layer height, and supports, please use the print settings MarcoZ76 recommends for his original design (30%, 2mm, with supports).

Big thanks to MarcoZ76 for his extruder, and to Bondtech for sharing the original design under a GPL license. Aside from the heat-set inserts, I'm using genuine Bondtech parts and recommend people do the same.