I wanted to use my Garmin Vista HCx GPS on different bicycles without the need of unscrewing/rescrewing the original Garmin bike mount everytime. This is especially cumbersome since the original Garmin part is made for a "huge" 30mm bar diameter, which means that for the normal 25mm bars, you need to carfully underlay it with several layers of rubber strips in order to fit the smaller diameter. So why not design and print my own handlebar mount on my RepRap? That way I can make it fit exactly my bar diameter and I can print as many a I need... Just as the original, the bar mount has a hinge, so that it can be easily opened up when attaching it to the handlebar. So there is no need to bend open the printed parts - which means that it can also be printed in the less flexible PLA. Two bolts are needed to assemble the bar mount: An M3x25mm with a corresponding nylon nut serves as axis for the hinge and a M4x25mm bolt is used to fasten the bar mount. The corresponding M4 nut fits tightly into the hexagonal cutout. I use the tip of my hot soldering iron to push the nut in firmly, so that it will never fall out again. The SCAD file provided is parametrized so that it can easily be adapted to specific handlebar diameters. Also the eTrex specific part is separated in a special module, so that the bar mount clamp part can used for other types of clip-on systems (I am planning to eventually adapt the file also for the newer Garmin eTrex 10/20/30 series). Three STL files are provided for handlebars with a diameter of 22mm, 25mm and 28mm - a range which should pretty much cover most of the more common bar diameters. Update 2013-10-12: I have extended this project now to also support the newer eTrex 10/20/30 series (as well as probably models of the Colorado, Dakota and Oregon series, which use the same slide rails) in http://www.thingiverse.com/thing:164720. As in the mean time I was also able to greately improve the bridging support, this new "thing" also includes updated STL files for the Legend/Vista C/Cx/HCx. So you might want to download the newer versions there. Update 2013-10-17: For those who can't find the clip-mount adapter which originally came with the GPS device I have now uploaded a printable version of it: http://www.thingiverse.com/thing:167082. Update 2013-10-27: I just uploaded a tiltable version of this bar mount. It can be used to mount the eTrex on non-horizontal parts of the handlebar, as it allows to compensate the skewness of the tube by tilting the slide rail up to 45 degrees: http://www.thingiverse.com/thing:172478 Update 2015-08-21: After almost 2 years of heavy use, yesterday the rail locks of my eTrex bar mount broke away when riding over a big hump. So I decided to make the new one with somewhat stronger mounting rails. So I have now uploaded the STLs and the SCAD file of the new stronger versions as well.