Drill hole test cube

thingiverse

This is a test print for flat-top screws/bolts. Two holes are present, one perpendicular to the layers and another parallel to them. I once worked on a major project involving 24 countersunk holes, but before investing hours in a test print, I needed to confirm their size was correct. To verify this, I created a mock-up that proved invaluable. The cube is precisely three holes wide, so it's best to scale the cube up to three times its intended hole size. Personally, I've found prints tend to shrink by 0.2-0.3mm plus an additional 0.1mm per every ten millimeters of outer dimension. Consequently, a three-millimeter hole will likely contract to two-point-seven millimeters, a two-centimeter ring will decrease by half a millimeter, and an eighty-millimeter disk should shrink down to seventy-nine millimeters. Keep in mind that your results may vary, but this equation is designed to help you make more accurate guesses from the start.