Are you having cooling troubles with your hotend? Filament jambs? Too much fiddling with cleaning up stuck filament and too many dis-assemblies? This is one good solution. This replacement x-carriage should help anyone out who prints with pla or abs. Many fiament jambs happen when the hotend becomes heat saturated higher up. Then filament softens then as the filament is driven downward it mushrooms out and jambs higher up in the nozzle.I didn't find one that I liked so I put this together to direct a nice cool flow of air to the upper portion of the hot-end. It takes a common 40 mm cpu/gpu fan and is a really clean method to attach a fan. I hope it is useful for everyone needing better cooliing for the hotend.I've uploaded the final V4 STL called "xcarriagev4done_fixed.stl". It has been passed through Netfabb and is only 2.6 megs compared to 12.3 megs for V3. It prints nicely without requiring any support. The fan mount clears the diagonals nicely and the bushings fit well, too.I should have a V5 with linear slides and a raised hotend but can't promise when it will arrive.Enjoy!Print it out and install it! The X-Carriage-V4 loads onto your build bed and prints on edge.edit < I used a heat gun to warm up the four corners where the bronze bushes press in. With a little heat they slid in smoothly. > /edit <I'm using my first version today and the little fan and duct does an awesome job. The MakerGear hotend can maintain 180 for PLA, but struggles for go any higher than maybe 185 C. I hope the plugged nozzles are a thing of the past with this upgrade. Good luck everyone and please let me know how it works out.I have uploaded V4. I just received my new hotends from hotends.com they look awesome btw :). The cooling fins were a few mms higher than I had expected so I re-contoured the air ramp and outlet to allow a better air flow a little higher up on the nozzle. The new fan bracket is thinner. It's just as strong but uses less plastic. Use the V4 x-carriage for both the Makergear hotend and for the hotend.com finned power resistor hotend.Talk about the "evolution of a design"! I wonder how many more changes I'll have to the idea! :)I've just uploaded new photos showing the new X-Carriage with the Birdnose extruder. They go very well together!I'm also working on a new x-carriage that raises the hotend 3 cm so the total Z travel on the MakerGear Prusa should be at or over 11 cm and it will use linear slides for near zero friction.