Summary So i backed the kickstarter for QUBD's dual extruder, and it arrives to much excitement only to find out that it is too short to mount on my Quick fit X carriage! So after hearing nothing from their tech support people about mounting it on a Prusa Mendel, I get to work designing my own mount. I designed a bowden connection to mount both hotends on a single alumium block, limiting the amount of build volume lost by the two heads, and combined that with a quick-fit plate for richrap's quickfit extruder. I use the poor man's 1.75mm bowden fittings of an M4 nut on 4mm teflon tubing, so that is what this is designed for. When testing is complete I'll publish updated stl and design files. Instructions Print. Install bowden tube. use two qubd extruders on a quick fit carriage.