Ender 3 Max X-Belt Raising Clamp

In the midst of chasing dimension accuracies for my Ender 3 Max, I faces issues with my printer limitation where the movement distance is non-linear. 

The idea came when I tried to do dimensional calibration from https://www.printables.com/model/778188-calistar-parametric-open-source-alternative-to-cal and found that the movement calibration may not be linear for Ender series or similar built printers as in the notes (X-carrier movement using single stepper motor and belt), where the belt by default is not parallel. (Refer discussion in : https://klipper.discourse.group/t/correct-dimensional-accuracy/6093/10)  

Another analogy : try to pull a box with a rope on ground at the same ground level VS pull the box on ground when you on a ladder, both pulling for 100mm. From your end (stepper motor) you are pulling rope by 100mm. Box on the ground will move 100mm when you are on the same level, but when you are on ladder, the box may move less than 100mm due to angle. 

This make the movement of the X accuracies at the dead center of my print bed (gantry center) more accurate to print small objects but when print large object , where X-Carrier constantly moving to the far left or right, the dimensions shrink.

There is a solution from https://klipper.discourse.group/t/dimensional-accuracy-problem/2370 where you can raise the belt level at hooking area to be parallel to the top belt to reduce the non-linear motion. However, I do not have extra belt and current belt is not long enough to do the tricks, plus I have quite a modded fan shroud so dissembly of the whole carrier is a big hassle, and hence designed this part to try out with minimal changes required. It works, at least all my dimensional accuracy using the calistar are back within tolerance that I am satisfied.

I printed this part in ABS as I have enclosure for my E3Max. PLA should be fine but try it out yourself.

Loosen your X-Carrier belt, try to hold the belt INTO the aluminium, slide/snap the part on the hook while belt route over the top of the part, make sure the part did not rub against the POM wheel, and the belt not rubbing the aluminium. Then do the necessary tensioning of your belt.

I did it only on the left side, and adjust the idler on the right side to lower the belt to make it parallel (seems like my idler is abit bigger in diameter than stepper motor side), while making sure no belt rub against the aluminium. However you can mirror the part and/or adjust as per required.

Edit V4 : increase some length and close up the clamp for more stability. (Some Enders may interfere with POM wheel so do double check)