diff --git a/cad/mechanics_rev3/dimensions.scad b/cad/mechanics_rev3/dimensions.scad
index 5355576..2f3c04c 100644
--- a/cad/mechanics_rev3/dimensions.scad
+++ b/cad/mechanics_rev3/dimensions.scad
@@ -54,7 +54,11 @@ myColor2 = "Maroon";
 drill_dia_m3 = 2.5;
 
 // Lids dimensions
-lids_depth = housing_thickness/4; 
+lids_depth = housing_thickness/4;
+ 
 lid_l_r_height = housing_inside_height/2;
 lid_l_r_width = (3/4)*housing_inside_depth;
 lid_l_r_overlap = (3/2)*housing_thickness; 
+
+lid_f_b_width = housing_inside_width + (1.0)*housing_thickness;
+lid_f_b_height = housing_inside_height + (1.0)*housing_thickness;
diff --git a/cad/mechanics_rev3/main.scad b/cad/mechanics_rev3/main.scad
index 168ec12..db88c29 100644
--- a/cad/mechanics_rev3/main.scad
+++ b/cad/mechanics_rev3/main.scad
@@ -44,21 +44,22 @@ difference()
 		translate([x*housing_outside_width/2 - x*lids_depth + x, 0, 0])
 		rotate([0, 90, 0])
 		roundy(lid_l_r_height + lid_l_r_overlap, lid_l_r_width + lid_l_r_overlap, lids_depth + 2, center = true);
+		// Front and back
+		for(y = [-1, 1])
+		translate([0, y*housing_outside_depth/2 - y*lids_depth + y, 0])
+		rotate([90, 0, 0])
+		cube([lid_f_b_width, lid_f_b_height, housing_thickness/4 + 2], center = true);	
 		// Top and bottom
 		for(z = [-1, 1])
 		translate([0, 0, z*housing_outside_height/2 - z*lids_depth + z])
 		roundy(housing_inside_width + (3/2)*housing_thickness, housing_inside_depth + (3/2)*housing_thickness, housing_thickness/4 + 2);
-		// Front and back
-		for(y = [-1, 1])
-		translate([0, y*housing_outside_depth/2 - y*housing_thickness/8 + y, 0])
-		rotate([90, 0, 0])
-		cube([housing_inside_width + (1.0)*housing_thickness, housing_inside_height + (1.0)*housing_thickness, housing_thickness/4 + 2], center = true);
-		
+	
 		// Screw holes
 		// Left and right
 		for(x = [-1, 1])
-		translate([0, x*housing_outside_height/2 - x*0.95*housing_thickness/2, 0])
-		screw_holes(housing_outside_width - (4/3)*housing_thickness, housing_outside_depth - (4/3)*housing_thickness, drill_dia_m3, housing_thickness/2);
+		translate([x*housing_outside_width/2 - x*housing_thickness/2, 0, 0])
+		rotate([90, 0, 90])
+		screw_holes(lid_l_r_width + (1/2)*lid_l_r_overlap, lid_l_r_height + (1/2)*lid_l_r_overlap, drill_dia_m3, housing_thickness/2);
 
 		// Top and bottom
 		for(z = [-1, 1])