QUBD : Bowden style x-carriage with hot-end metal holder

Originally, I used a hotend holder made from PLA. It worked great for a few days, but it had shifted and gotten lose over the time. I'm afraid it too hot for PLA material even at top side of hotend.

So, I used the metal holder.

http://www.amazon.com/gp/product/B00G9FQYTG  

I'm using this almost 2 weeks, and haven't noticed any shift or looseness.
So, I consider using the metal holder solved the problem.

My design owes most of part to this design.

http://www.thingiverse.com/thing:408818  

The changes I made are

• Change the hole location to align with the above metal holder.

• Widen 1[mm] the belt teeth and guide

  Somehow, my pulley belt is ticker and hard to fit the original design.
  If yours are thinner belt and lose to fit my design, put pieces of small paper to fill the gap.