$fn=36;

ep = 0.01;
height = 4.5;

iDepth = 3.5;
oDepth = 9;

iWidth = 13;
oWidth = 20;

clipWidth=5;

overhang=5;

pinClear = 2.2;   // pin clearance
slideClear = 1.8;

union() {
  // base bracket
  difference() {
    translate([-oWidth/2, 0, 0]) cube([oWidth, oDepth, height + ep]);

    translate([-iWidth/2, -ep, -ep]) cube([iWidth, iDepth + ep, height + 3*ep]);
  }

  // clip
  difference() {
    translate([-clipWidth/2, -overhang, height]) cube([clipWidth, oDepth + overhang, 4]);

    color("red") union() {
      translate([-oWidth/2, -2.5, height + 1.25]) rotate([0, 90, 0]) cylinder(d=3, h=oWidth);
      translate([-clipWidth/2 - ep, -overhang - ep, height - ep]) cube([clipWidth + 2*ep, overhang + ep, 1.5 + ep]);
    }
  }
}