Testing the lasered pieces is probably the most important lesson learned here. Not just once either, many tests may be necessary in order to get the perfect fit you want. My nut and bolt fit rather snugly, but they could certainly have fit better; they still pop out with ease. For my design, I was thinking along the lines of boxes, but I didn't want something so plain. By taking out opposite corners on the box, it allowed me to create different relations between the pieces while they are being screwed together.