9 hole_from_back = 7.2 + 0.5;
11 bolthead_dia = 7 + 1.0;
14 height = light_height + backspc;
16 octagon_fudge = 1/cos(22.5);
20 translate([-len/2, 0,0])
21 cube([len, width, height]);
23 translate([xsgn * holespc/2, -1, light_height - hole_from_back]) {
25 rotate([0,0,360/8/2]) {
26 cylinder(r=bolthead_dia/2 * octagon_fudge,
27 h= bolthead_depth +1, $fn=8);
28 cylinder(r=hole_dia/2 * octagon_fudge,