About this 3D model

I Had a problem when using a PLA bushing for my new prusa x-carriage, i found that a PLA bushing seem no good to holding on a X Axis Rod and make it less gap btw them. So, i redegin a whole x-carriage by using a PTFE as a bearing and I also using a two side screw tensioner fit onto x-carriage, it works very fine for me to tightened X axis belt just by (un-tightened 2nos M3 belt clamps screw + turning screw tensioner as you want how x belt to be tighten). However, I notice that this design may be no suitable for whom who is using a two supporting screw to holding a hot-end nozzle, due to the opening of this carriage is not to big. (What i'm using is PEEK sleeve inside with PEEK thermal barrier, So, i dont need that supporting screw.) BOM List. 1. PrusaXCarriagePTFEbearing RP x1 2. PrusaCarriageBeltClamp RP x1 3. 12mm or 12.5mm PTFE ROD with 8.2mm hole x2 4. 7mm dia screw tensioner x1 5. m3 nut x6 6. m4 nut x2 7. m3x20 x6 8. m3x12 x4 9. if you interesting to using my another Wades Geared Extruder + Thermal barrier clamp -> http://www.thingiverse.com/thing:5577