This is spacer design for Da Vinci 1.0 Y axis drive pulleys. The Da Vinci 1.0 Y axis drive rod has some gape between pulley and E-clips and create some backlash. If you print small circle the effect of the backlash will shows up and end up with not rounded circle. The gap is around 0.75 mm on my printer. I fix it with spacer made form used gift card. The pdf file has template for cutting spacer. The 3D model also provided in case you want to try print the spacer. With the spacer will improve the print quality. You can see the full discussion at http://voltivo.com/forum/davinci-hwmods/78-cracked-y-axis-bearing-holder
Make 3 spacer and install on Da Vinci's all 3 Y axis drive pulley in the back of the printer. if you print the spacer make sure the they fits tight on your printer pulley.