Remix of i3v 10" Prus Makerfarm X-Carriage with rounded corners & fillet welds

I liked the idea of having a spare part of this in plastic although I have read that it may have some problems with the plastic being too close to the hotend. I modified http://www.thingiverse.com/thing:481769 to have rounded corners & a little more support at the 90 connections of the plastic with 2 fillet welds.

I uploaded a rev2 of this part after noticing the original that I remixed from was missing a hole for the gear shaft. I made this a symmetrical slotted hole to use less plastic.