About this 3D model

This is the 5th version of my printable linear rail, I've gotten everything to finally work correctly. This can be used as a drop in replacement for a 3d printer's X or Y axis. It's rail system is designed to connect together to form any needed length. This machine hopefully will be my entry for the Gada prize. Update 06/16/2011:I worked out a few modifications to the shuttle. Now the lower half of the shuttle can be printed as well, this removes:4x 5/16(8mm) nuts2x 5/16(8mm) bolts2x 5/16 washers -The next to go is going to be replacing the front 5/16(8mm) hardware with all printed parts. I'm trying to pare this down just the motor and the printed parts. -I also redesigned the Large helical gear to incorporate the 608 bearing embedded inside of it. think this is an advantage of trying to use 2 bearings in the pillow block. The large helical gear is also now held in place by a printed 8mm bolt 40mm long. This removes one additional piece of hardware. -The shuttle top now has 4 mounting holes, although I'm just securing the motor with 2 at this point. -I printed 2 new 3-segment rails, redesigned lower half of shuttle to be printed.-I also added 2 new pics of the x/y gantry system and uploaded all new parts - I should have another video. Update 04/30/2013It's been brought to my attention that the rack file was missing from this. I have uploaded both the rack stl and scad file. Enjoy! Here is a youtube video of it in action:http://www.youtube.com/watch?v=ScJMPw6UPtw Comments and feedback are welcome.