Nice work! I am guessing the idea here is to be able to get a better grip on the filament to push it faster? I have two questions? Would adding this extra mass to a direct print head cause problems when you run the printer at accelerated speeds and secondly, if the first hobbled bolt impressed the filament, is this going to cause problems with the second hobbled bolt gripping the filament? In my mind this seems like the second hobbled bolt might just grind grind up the already roughened up filament? Perhaps I am over thinking it?