diff --git a/notebook_nueva/keyboard.py b/notebook_nueva/keyboard.py
index 65a51a9..df41c68 100644
--- a/notebook_nueva/keyboard.py
+++ b/notebook_nueva/keyboard.py
@@ -90,8 +90,9 @@ def add(
                 cq.Sketch().polygon(
                     [
                         [0, front_thickness],
-                        [actual_height, back_thickness],
-                        [actual_height, 1000],
+                        [shell_t, front_thickness],
+                        [actual_height + shell_t, back_thickness],
+                        [actual_height + shell_t, 1000],
                         [0, 1000],
                         [0, front_thickness],
                     ]