One of two fully parametric project boxes, one with 4 screws to attach the lid, and one with 6 screws, for larger boxes. Otherwise the designs are identical. The lid has a lip which fits inside the bottom walls. These designs are public on Onshape.com. The links are: 4-hole box: goo.gl/ZdkVYM 6-hole box: goo.gl/v9E0Rr You can view the designs, and copy them into your own Onshape workspace to modify them.

The parameters are:

Width, Length, Height: overall outside dimensions LidHeight: Height of the lid portion, not including the lip on the lid WallThickness: thickness of all six walls (top, bottom, 4 sides) CornerRadius: radius of the four corners LidFaceRadius: Radius of fillet around the face of the lid BottomRadius: Radius of fillet around the bottom face Clearance: used between the lid screw bosses and the bottom screw bosses, and also between the lip and the bottom inside edge LipHeight: amount the lip (and lid bosses) extend below the bottom edge of the lid LipThickness: wall thickness for the lip HoleInset: distance the screw holes are inset from the outside edges LidHoleID: ID for screw clearance hole thru lid LidBossOD: diameter of the lid bosses BotBossID: diameter of hole in bottom bosses. Set this to hold a sheet metal screw or thread insert if one is used BotBossOD: diameter of the bottom screw bosses CornerBraceWidth: width of the braces from the bosses to the walls on the bottom piece BotBossHoleDepth: blind hole depth of the screw holes in the bottom screw bosses

Note: for most 3D printers, the face fillet radii need to be small, as these features are not well reproduced on a 3D printer.

It's intended that a copy of this box would be used as the basis for a specific project box design, adding holes and other features needed by the project.