Auto belt tightener for x axis

I was building my huxley (it's still not running) and I noticed that tightening the belts was not so easy. too loose and it skipped and too tight and it binds and sometimes it would not run. so I downloaded some stl files from Techzone and modified them. here is the first one, the X axis module. I hope it is useful and when some one prints one and its not to expensive you can send me one so I can see if im doing things right, or if I have to modify it, thanks.
that part should work with most of the printers out there.
z is next and y later