This knob / thumbdial / thumbwheel is designed for the Alfawise U20 heatbed.
Other models here on Thingiverse (for the CR-10) are designed for different knobs and don't work with the Alfawise U20.
This upgrade is designed to include the 18 teeth original adjusting knobs. You don't need to scale it, tolerances are already good. I tried to make it printable as fast as possible, it will take 1,5/2 hours to finish.
BUY - Alfawise U20 3D printer
LEARN MORE - If you own an Alfawise U20, I strongly suggest you to buy TL-smoothers to fix the salmon skin issue
DOWNLOAD - Filament guide upgrade designed by me