// -*- C -*-

cubez = 12;

shaftz = cubez;

tests = [[4 + 0.5,  10 + 1.0]];

cubexy = 20;

module RecessScrewCutout_RecessCylinder(recessdia,zbelow, h){
  translate([0,0,-zbelow]) cylinder(r=recessdia/2, h=h+1, $fn=40);
}

RecessedScrewCutout_defaultrecessdepth_flat = -0.35;
RecessedScrewCutout_defaultrecessdepth_hex = -0.70;

function RecessedScrewCutout_recessdepth(recessdia, recessdepth_arg) =
  recessdepth_arg >= 0 ? recessdepth_arg : -recessdepth_arg * recessdia;

function RecessedScrewCutout_totaldepth(recessdia, recessdepth_arg) =
  RecessedScrewCutout_recessdepth(recessdia, recessdepth_arg) +
  + 0.5*recessdia + 0.1;

module RecessedScrewCutout(shaftdia, recessdia, shaftlen,
        zbelow=1,
        recessdepth_arg=RecessedScrewCutout_defaultrecessdepth_flat) {
  // pass recessdepth_arg=-1 for the default for flat heads
  // pass recessdepth_arg=-1 for the default for flat heads
  recessdepth = RecessedScrewCutout_recessdepth(recessdia, recessdepth_arg);
  recesstopz = RecessedScrewCutout_totaldepth(recessdia, recessdepth_arg);

  translate([0,0,-zbelow]) cylinder(r=shaftdia/2, h=shaftlen+zbelow, $fn=20);
  RecessScrewCutout_RecessCylinder(recessdia,zbelow, recessdepth);
  intersection(){
    cube([recessdia + 1, shaftdia + 0.1, recesstopz*2 + 1], center=true);
    translate([0, -recessdia, recesstopz])
      rotate([0,135,0]) cube([recessdia, recessdia*2, 10]);
    RecessScrewCutout_RecessCylinder(recessdia,zbelow, recesstopz+1);
  }
}

module Test(){
  difference(){
    translate([-cubexy/2, -cubexy/2, 0])
      cube([cubexy,cubexy,cubez]);
  }
}

module Hole(){
    RecessedScrewCutout(tests[0][0],
			tests[0][1],
			shaftz+1);
}

//Test();
Hole();