Don't use this anymore There are way better designs in the meantime, by whpthomas and others, and this thing is outdated like the original extruder update by infinityplusplus, but made for a larger spring (~28x10mm) needs the same additional parts (bearing, screws) as the original from infinityplusplus, except for a m3 x 6mm screw for the top-right and the spring. had to change some dimensions of the original, in order to make room for the spring