Background: Though it might be easier for me to machine an entirely new and larger Cyclops style hotend, I decided to support E3D open source development and I purchased a Cyclops and two V6 3 mm heat breaks from my U.S. E3D dealer, PrintedSolid. I plan to modify the Cyclops for use with my highly modified 3 mm Ultimaker Original. I can easily increase the filament and melt path diameters fully through the heat sink and my newly sleeved V6 heat breaks. I believe that the entire assembly can support 3 mm filament all the way to the Cyclops heat block but that's where the path gets tight. The Cyclops heat block and nozzle melt paths are quite small (even for 1.7 mm). My question: I think I have room to drill / mill out the Cyclops heat block "cross paths" and nozzle melt path slightly (and even the entrance to the nozzle), but do you think I might be able to extrude from a 3 mm melt source though the heat block assembly, even as-is, after enlarging the path to 3 mm all the way through the heat break? Is it worth a try to leave the Cyclops heat block paths small or should I do what I can to increase their diameter before gooping everything up with melt in my first trial run? I have dual drive filament feeders and they are quite strong. I also purchased about a dozen 3 mm V6 nozzles and I'm nearly certain that, even if the Cyclops can't be modfied to work with 3 mm filament, I can get a Chimera style heat block setup to work. I probably have somewhere around 40 kg of 3 mm filament so I"m not converting to 1.7 mm anytime soon! I'd sure appreciate the opinions of others who have actually done hot end development.