ok, this is a last ditch effort to get my bowden cable to stay in place. it looks like it is holding so far. try it yourself and see if it works for you. it uses a bunch of small nails to bite into plastic tubing be it teflon or polypropylene. included is a parametric file that you can change for example if you want to use screws.use the stl file, or make your own with the scad file. it aint perfect, but you can figure the things to change easily. i make the nail length smaller than needed to ensure i have room to spike the nail in real good. it looks evil when the spikes are way out there! use with wades block, and this mount for ultimaker http://www.thingiverse.com/thing:148221) print out object 2) clean up 1/4 inch hole and size it with drill, make it snug with the tubing that goes inside it.3) place tubing inside it, then place a drill bit end, or something that fills the void that is strong and likely will not allow a nail thru inside the tubing4) hammer tap in the nails into the tiny holes in the side. you want enough force that the tubing is pierced.5) repeat for the rest of the nails.6) pull out part that was inside the tubing.7) now with an allen wrench wiggle around the inside of the tubing. you want the points of the nail to stop at just the point where it breaks thru the inside diameter of the tubing8) place this part in a wades extruder, then feed your feedstock thru. happier days now wait you.9) tell people about this ugly thing!