3 Inch Mending Plate

This is a hole, not a shape! I use this in Tinkercad.

This shape matches a 3 inch mending plate which I use for mounting plates inside some of my designs. Make it a hole and drag it into your design, and you will be able to fit a standard mending plate in the hole that you can then use to screw your design to a wall, or piece of wood, or your car or whatever. Better than washers!

This picture is in a project box I designed for a Raspberry Pi and some other items. The floor of the box is 5mm, the depth of the mending plate is about 3mm. This seems to give plenty of strength and it's flush with the floor. Careful not to ground electronics out on it.