Anybody better than me in CAD who wants to take over this mod?

I'll be happy to help but won't get to it for a couple of days.
PM me with more descriptive details.

Very nice work again!  The drilling shouldn't be too bad.  Hopefully everything is thick enough to avoid any cracking.  I will print 100% infill with ABS and nylon and see what works.  This is probably better than the old version mod that I had in mind since there is only 1 screw to tighten instead of 2.  I might put some flanged bearings on it instread of the stock pulleys.  Thanks!

Edit: Just taking another look and I'm not entirely convinced that the inner piece offers enough range on the adjustment before the end of the bolt would hit the pulley.  But then again you don't need much so I'll know for sure once I assemble it.  I guess the key would be to tension it when it is all the way out then crank down on it only as much as needed.

PS: Pirvan, I printed your new carriages in nylon and ABS this weekend.  I'm not convinced that nylon is any better than ABS for the main carriage bodies but the nylon was great for the belt clips since it is less brittle in the thin pieces.  I've got an idea for a tension-able adjustment in mind for the X idler too that would involve a nut trap similar to this design.  Want me to send you a sketch?

Does the solidoodle have enough "range" to put those on the belts?  Obviously, you can't pass that around the idler and I'm thinking it might collide.  When I get home I'm going to try to seperate the pieces of your tensionsers in netfabb so I can print them without being that close together.

Makes sense but I just wasn't sure since it does have a certain length to it. 

Anyway, folger tech also sells these, probably a little quicker than most ebay sellers. 

My only complaint is that its too simple, I like a big contraption to solve these minor problems

Move your print head to it's homed position (all the wayback), then add the spring on the top part of the belt,  at the opposite end as close to the idler pulley as it can go without touching anything (about 1/4" before it reaches the idler pulley block).

When the print head moves all they way to the front, the belt and the spring will move back there shouldn't be any interferences, with the possible exception of the 5mm bolt on the right carriage, which overly long, and should be cut down to length anyway, or inverted so the socket head is on top.

mdrVB6 wrote:
My only complaint is that its too simple, I like a big contraption to solve these minor problems

I love Rube Goldberg contraptions myself, but simplicity is the mother of elegance.