diff --git a/cad/openscad/stamp_holder.scad b/cad/openscad/stamp_holder.scad
index 30962c5..3ff7eac 100644
--- a/cad/openscad/stamp_holder.scad
+++ b/cad/openscad/stamp_holder.scad
@@ -20,17 +20,11 @@ module middle() {
 linear_extrude(height=wall_thickness) {
     common();
     translate([-size / 2, 0])
-        round_rect((wall_thickness+output_thickness)*2,size/2,[1,1,1,1]);
+        round_rect((wall_thickness*3/2+output_thickness)*2,size/2+wall_thickness/2,[1,1,1,1]);
 }
 
 translate([0,0,wall_thickness]) difference() {
-    linear_extrude(height=internal_height) {
-        middle();
-        hull() {
-            translate([-size/2-output_thickness-wall_thickness/2,size/4-wall_thickness/2]) circle(wall_thickness/2);
-            translate([-size/2-output_thickness-wall_thickness/2,-size/4+wall_thickness/2]) circle(wall_thickness/2);
-        }
-    }
+    linear_extrude(height=internal_height) middle();
     translate([0,0,internal_height*1/2]) {
         rotate([0,0,-30]) rotate_extrude(angle=60) square([center_radius-1,1]);
         rotate([0,0,150]) rotate_extrude(angle=60) square([center_radius-1,1]);
@@ -38,6 +32,12 @@ translate([0,0,wall_thickness]) difference() {
     }
 }
 
+translate([0,0,wall_thickness]) linear_extrude(height=internal_height+wall_thickness) hull() {
+    translate([-size/2-output_thickness-wall_thickness/2,size/4-wall_thickness/2]) circle(wall_thickness/2);
+    translate([-size/2-output_thickness-wall_thickness/2,-size/4+wall_thickness/2]) circle(wall_thickness/2);
+}
+
+
 translate([0,0,wall_thickness+internal_height]) linear_extrude(height=wall_thickness/2) {
     intersection() {
         middle();
@@ -47,10 +47,4 @@ translate([0,0,wall_thickness+internal_height]) linear_extrude(height=wall_thick
             
         }
     }
-    hull() {
-        translate([-size/2-output_thickness-wall_thickness/2,size/4-wall_thickness/2]) circle(wall_thickness/4);
-        translate([-size/2-output_thickness-wall_thickness/2,-size/4+wall_thickness/2]) circle(wall_thickness/4);
-    }
-
-
 }
\ No newline at end of file
diff --git a/cad/openscad/stamp_holder_top.scad b/cad/openscad/stamp_holder_top.scad
index 705d428..b10e2d3 100644
--- a/cad/openscad/stamp_holder_top.scad
+++ b/cad/openscad/stamp_holder_top.scad
@@ -1,24 +1,46 @@
 include <stamp_holder_common.scad>
 
 module finger() {
-    translate([center_radius-wall_thickness*2-0.25,0,0]) square([wall_thickness,internal_height*1/3]);
+    translate([center_radius-wall_thickness*2-0.25,0,0]) square([wall_thickness,internal_height*1/3-2]);
 }
 
 module hook() {
-    translate([center_radius-wall_thickness*2-0.25,0,0]) {
-        square([wall_thickness,internal_height*1/3+2]);
-        translate([wall_thickness,internal_height*1/3])
+    translate([center_radius-wall_thickness*2-0.25,0]) {
+        square([wall_thickness,internal_height*1/3+1]);
+        translate([wall_thickness,internal_height*1/3-1])
             polygon([[0,-1],[1,0.5],[0,2]]);
     }
 }
 
-linear_extrude(wall_thickness) {
+module alignment_socket() {
+    hull() {
+        translate([-size/2-output_thickness-wall_thickness/2,size/4-wall_thickness/2]) circle(wall_thickness*5/8);
+        translate([-size/2-output_thickness-wall_thickness/2,-size/4+wall_thickness/2]) circle(wall_thickness*5/8);
+    }
+}
+
+linear_extrude(wall_thickness/2) {
     difference() {
         mirror([1,0,0]) {
             translate([0,(wall_thickness+output_thickness)/2])
                 round_rect(total_length, total_width, [5, 5, 15, 1]);
             translate([-size / 2, 0])
-                round_rect((wall_thickness+output_thickness)*2,size/2,[1,1,1,1]);
+                round_rect((wall_thickness*3/2+output_thickness)*2,size/2+wall_thickness,[1,1,1,1]);
+        }
+        circle(center_radius-wall_thickness*2-0.25);
+    }
+}
+
+translate([0,0,wall_thickness/2]) linear_extrude(wall_thickness/2) {
+    difference() {
+        mirror([1,0,0]) {
+            translate([0,(wall_thickness+output_thickness)/2])
+                round_rect(total_length, total_width, [5, 5, 15, 1]);
+            difference() {
+                translate([-size / 2, 0])
+                    round_rect((wall_thickness*3/2+output_thickness)*2,size/2+wall_thickness,[1,1,1,1]);
+                alignment_socket();
+            }
         }
         circle(center_radius-wall_thickness*2-0.25);
     }
@@ -30,14 +52,10 @@ translate([0,0,wall_thickness]) linear_extrude(wall_thickness/2) {
             translate([0,(wall_thickness+output_thickness)/2])
                 round_rect(total_length-wall_thickness-.5, total_width-wall_thickness-.5, [5, 5, 15, 1]);
             difference() {
-                hull() {
-                    translate([-size/2-output_thickness-wall_thickness/2,size/4-wall_thickness/2]) circle(wall_thickness/2);
-                    translate([-size/2-output_thickness-wall_thickness/2,-size/4+wall_thickness/2]) circle(wall_thickness/2);
-                }
-                hull() {
-                    translate([-size/2-output_thickness-wall_thickness/2,size/4-wall_thickness/2]) circle(wall_thickness*3/8);
-                    translate([-size/2-output_thickness-wall_thickness/2,-size/4+wall_thickness/2]) circle(wall_thickness*3/8);
-                }
+                translate([-size / 2-output_thickness-wall_thickness/2, 0])
+                    round_rect(wall_thickness*2,size/2+wall_thickness,[1,1,1,1]);
+
+                alignment_socket();
             }
         }
         circle(center_radius-wall_thickness*2-0.25);
@@ -53,5 +71,4 @@ translate([0,0,wall_thickness*3/2+internal_height/6]) {
     rotate([0,0,35]) rotate_extrude(angle=110) finger();
     rotate([0,0,155]) rotate_extrude(angle=50) hook();
     rotate([0,0,215]) rotate_extrude(angle=110) finger();
-
 }
\ No newline at end of file