I wanted to experiment with different nozzle diameters. I bought an E3D v6 Nozzle with 0.6mm nozzle size. It has just like the Ulimaker nozzle a M6 thread. But you cannot use the original fan mount because the E3D nozzle is shorter than the original Ultimaker nozzle. So here's a solution. The fanmount takes less space then the original. But you need a 40mm fan. edit: added secondary fan shroud for dual fan. changed to 40mm x 40mm x 10mm sized fans.