// A 100 mm square with a 20 mm hole, for checking size and kerf.
// Measure both after cutting. If the square is small and the hole is big,
// raise $kerf by the difference; if it is the other way round, lower it.

/* [Size] */
// Outside of the square
size = 100; // [20:5:300]
// Diameter of the hole
hole = 20; // [2:1:100]

/* [Material] */
$kerf = 0.15; // [0:0.01:0.5]

difference() {
  rect(size, center = true);
  circle(d = hole);
}
score() rect(size / 2, center = true);
engrave() {
  translate([0, -size / 2 + 6]) text(str(size, " mm"), size = 4, halign = "center");
  translate([0, hole / 2 + 4]) text(str("hole ", hole, " mm, kerf ", $kerf), size = 3, halign = "center");
}