Easy-grip Bed Leveling Knob for Ultimaker 2

I find the bed leveling screw on the Ultimaker 2 difficult to rotate due to its small size and lack of grip so I made this knob that is thin enough to fit in the gap between the bed and bottom of the printer while being big enough that allows for easy rotation the bed leveling screw.

Play with Cura's Horizontal Expansion to make the hole tight enough to fit the screws. I printed with 0.1mm horizontal expansion and it's the perfect fit on mine.