diff --git a/light-switches/gfci-paddle-switch-extended-offset.scad b/light-switches/gfci-paddle-switch-extended-offset.scad
index 593fc1b..7e54929 100644
--- a/light-switches/gfci-paddle-switch-extended-offset.scad
+++ b/light-switches/gfci-paddle-switch-extended-offset.scad
@@ -107,16 +107,18 @@ module paddle_opening_3d() {
 module screw_holes() {
     if (screw_holes_enabled) {
         // Main screw holes: recessed from back face (positive Z), solid wall on front
-        main_screw_start_z = plate_thickness - main_screw_recess_depth;
+        // Start slightly below target to ensure clean CSG intersection
+        main_screw_start_z = plate_thickness - main_screw_recess_depth - 0.01;
+        main_screw_cut_height = plate_thickness - main_screw_start_z + 0.1;
 
         // Top main screw hole (pill-shaped, horizontal)
         translate([0, screw_hole_spacing/2, main_screw_start_z])
-            linear_extrude(height = main_screw_recess_depth + 0.1)
+            linear_extrude(height = main_screw_cut_height)
                 rect([screw_hole_width, screw_hole_height], rounding=screw_hole_height/2);
 
         // Bottom main screw hole (pill-shaped, horizontal)
         translate([0, -screw_hole_spacing/2, main_screw_start_z])
-            linear_extrude(height = main_screw_recess_depth + 0.1)
+            linear_extrude(height = main_screw_cut_height)
                 rect([screw_hole_width, screw_hole_height], rounding=screw_hole_height/2);
     }
 
diff --git a/light-switches/gfci-paddle-switch-extended.scad b/light-switches/gfci-paddle-switch-extended.scad
index ca397e4..40deab5 100644
--- a/light-switches/gfci-paddle-switch-extended.scad
+++ b/light-switches/gfci-paddle-switch-extended.scad
@@ -101,16 +101,18 @@ module paddle_opening_3d() {
 module screw_holes() {
     if (screw_holes_enabled) {
         // Main screw holes: recessed from back face (positive Z), solid wall on front
-        main_screw_start_z = plate_thickness - main_screw_recess_depth;
+        // Start slightly below target to ensure clean CSG intersection
+        main_screw_start_z = plate_thickness - main_screw_recess_depth - 0.01;
+        main_screw_cut_height = plate_thickness - main_screw_start_z + 0.1;
 
         // Top main screw hole (pill-shaped, horizontal)
         translate([0, screw_hole_spacing/2, main_screw_start_z])
-            linear_extrude(height = main_screw_recess_depth + 0.1)
+            linear_extrude(height = main_screw_cut_height)
                 rect([screw_hole_width, screw_hole_height], rounding=screw_hole_height/2);
 
         // Bottom main screw hole (pill-shaped, horizontal)
         translate([0, -screw_hole_spacing/2, main_screw_start_z])
-            linear_extrude(height = main_screw_recess_depth + 0.1)
+            linear_extrude(height = main_screw_cut_height)
                 rect([screw_hole_width, screw_hole_height], rounding=screw_hole_height/2);
     }