adjustable width LM8 Y-Carriage for Mendelmax with strong bearing holders

update: 11/8/13 (ish) i uploaded a picture of this mounted on my machine. when you mount it the side that printed against the bed should be up(twards the heat spreader) and the russ bot monogram should down. the top belt clamps are pretty much just guides the clamping happens on the bottom(down side)..
this is simaller to the tommy c carriage however i kept breaking off the bearing ears. so i decided to make one that used a vertically printed bearing holder. I did not include a belt tension-er because i have the external one on my Max. I also included adjustable ears so you set the bearing width to the exact size of your rails. i have only printed the first rendition but have included the more pleasing (and stronger version) that i worked up while the first carriage was printing. I will leave this tagged as a work in progress until test the "light" version or some one else reports that it works. NOTE: I have not mounted this yet, it prints and all the parts line up. i will update when its up and running.
let me know if anything is broken or could be improved!
UPDATE 1/25/13 : The Light carriage could not be sliced, i have uploaded a new fixed file.
UPDATE: I have now been running the first version on my Max for long enough to report that is works like a charm. Very stable. I may redesign to include a belt tentioner because I am not all the fond of the external tentioner wobbling as a adjust it causing some belt alignment issues. Of course it may be easier to just tell design the external tentioner