The LulzBot TAZ 5 User Manual has this mysterious section:
5.4 Using 1.75mm filament
Your LulzBot TAZ 3D printer is set up to use 3mm plastic filament by
default and may be capable of printing 1.75mm filament with no hardware
modification. While many of our advanced users are able to do so, your
results may vary.
Since we wanted to use the remaining glow-in-the-dark filament, we decided to
try our luck. So we changed the filament diameter to 1.75mm in Slic3r, and
printed a few small objects. Everything went as expected, only the retraction
moves didn’t work so well and the filament oozed out of the extruder
nonetheless. But those strands can easily be cleaned up later, so we went on
with some bigger objects. This was when the printer would reproducibly stop
extruding after a few layers, and it seemed like the nozzle was clogged up.
Investigation showed this beauty:
![](/blog/images/posts/2016-09-23-lulzbot-1.75mm-filament/curl.jpg)
Apparently the filament was too thin to be directed into the hotend, so it
decided to curl up in the space between the hobbed bolt and the upper entry of
the nozzle instead. After all, the manual was right, our results really did
vary.