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.thingiver