All steel hot end for Makerbot

thingiverse

This alternative extruder hot-end design may work with other 3D printers too, as it does not require insulators like PTFE or PEEK. It employs a stack of washers and nuts as heatsinks to reduce temperature. The creator found it effective, heating up in less than a minute from 25 to 220 degrees Celsius, without stalled extruders, stuck filaments or halfway prints. They've only printed with ABS, though, so the success with other materials is uncertain. The design uses a 65mm long M6 bolt, drilled through its entire length with a 3.2mm hole. It also requires cutting down the makerbot nozzle and creating a heater using a threaded insert wrapped in nichrome wire. The heatsink consists of a stack of M6 nuts and 25mm M6 fender washers, notched to fit between the standard MK4 extruder's retainer washers. A small fan is needed to cool the heatsink. To drill the bolt through its entire length, use a lathe if possible or the "afghan lathe" method or a drill press. Drilling from both sides might result in misaligned holes; in that case, enlarge the hole at one end for better filament feeding. The heater and nozzle should be secured tightly together. Assemble everything using M4 bolts from the standard MK4 extruder and insulate with a thermistor and blanket. Mount the fan on the extruder platform with hot glue to cool the heatsink.