// -*- C -*-

arm_depth = 25;
arm_pindepth = (16.15 + 18.00)/2;
arm_innerwidth = 9.60 - 0.50;
arm_innerheight = 8.90 - 0.50;

armpart_hex_rad = 15;
armpart_hex_thick = 8;

hingepin_dia = 3;

// computed

armpart_x_unit = armpart_hex_rad * tan(30);

module ArmPart(){ ////toplevel
  translate([-arm_innerwidth/2, 1, 0])
    mirror([0,-1,0])
    cube([arm_innerwidth, arm_depth+1, arm_innerheight]);
  rotate([90,0,180])
    linear_extrude(height=armpart_hex_thick)
    for (mir=[0,1])
      mirror([mir,0,0])
	difference(){
	  polygon([[-1, 0],
		   [armpart_x_unit, 0],
		   [armpart_x_unit*2, armpart_hex_rad],
		   [armpart_x_unit, armpart_hex_rad*2],
		   [-1, armpart_hex_rad*2]]);
	  translate([0,armpart_hex_rad])
	    circle(hingepin_dia/2, $fn=20);
        }
}

ArmPart();