Maker publishes open-source Klipper nozzle-cleaning macro for Rat Rig V-Core 4.1's True Zero calibration

Rat Rig's 4.1 update for the V-Core printer series introduced a new Z-axis calibration routine called True Zero, but heating the nozzle before measurement can push out filament residue and skew the reading, and Rat Rig shipped no cleaning macro to prevent it. A third-party maker published an open-source fix on Printables: a redesigned wiper holder plus a Klipper macro called CLEAN_NOZZLE. The holder mounts through two holes on the back of the bed rather than the felt wipers in Rat Rig's own design, which reportedly loosen and can collide with custom tool heads near the Z-spindles. It is printed in carbon-fiber-reinforced PPA rated to 190 degrees Celsius, with a silicone wiper insert sourced from a Qidi Plus 4.

The macro runs ten wiping passes at 300 millimeters per second after a 60-second dwell to let the nozzle fully ooze, adding roughly one to two minutes to each print start on a 400 by 400 millimeter bed, with offsets adjustable for the 300 and 500 variants. This is a community fix, not an OEM release, and it reflects a common pattern in desktop and prosumer FDM: vendors ship a calibration feature ahead of the surrounding workflow, and the open Klipper ecosystem often closes that gap faster than the official roadmap. V-Core 4.1 owners chasing repeatable Z-offset accuracy currently need a third-party macro to get clean True Zero readings.