The thickness of plank it is made for is 18.5mm, this has to fit the plank you're using. If your plank is a little thinner you can use (sufficiently high friction, like mask-) tape to make it clamp better. If it is too far off you'll have to use the .scad file yourself. Note that i made improvements on the designs after that photo.(also the print is poor because i was experimenting higher speeds and layer height)