X-axis Tensioner for Wanhao Di3

What
This is my X axis tensioner. There are many like it, but this one is mine.
Consideration is taken to allow space for the extruder motor cable if you want to rotate the motor (to move the cable from the top of the motor to the back).
The grip holding the belt is visible through a slot in the front, allowing you to see how much you can tighten the screw before it bottoms out.

Why
For easy adjustment of the X belt tension. I use a guitar-tuning app to tune the tension of my belts to 100Hz. Please note that I do not know what the perfect tension is or how accurate the app is. This is what I feel is at the upper end of the right amount of tension. Tightening too much can rip the belt or skew the printer..
Move the carriage to one side and pluck the lower belt with the phone mic close to the belt.

Hardware needed
1 M4x20mm (re-use one of the stock screws)
1 M4x10mm (can be left out)
1 M6 nut
1 M6x30mm or x35mm screw with cylindrical or round head with max Ø10mm.

Print recommendations
Print everything without supports, in the direction they appear.
Print the body at 0.16mm layer height, 15% infill.
Print the grip at 0,12mm layer height.
If you are only printing at PLA temps, you can use PLA for this. PETG or ABS is recommended for anything hotter. But make sure you can print them with good layer adhesion.
Preferably print the Lock and Grip in a different colour.

Installation
See pictures
Remove the screws holding the belt and the springy thing on the belt.
Remove the zip-ties on the right side of the belt but leave the outer one on the left side (seen from the back of the printer).
Re-use one of the M4x20 screws to mount the XTensionerBody. Optionally add M4x10 screw in the second hole. Make sure the body is parallel to the belt to prevent the belt from rubbing.
Insert the XTensionerLock in the slot and give the belt a pull.
Cut the other end of the belt just long enough for the XTensionerGrip to enter the body with the belt and a few extra millimetres.

If you haven't already, you can work through some more of the extruder motor cable through the cable-chain and run it between the lower rod and the XTensionerBody. Gives ome extra room when printing at the upper Z limit.