diff --git a/nhf/parts/box.py b/nhf/parts/box.py
index ebd5d63..69a40f8 100644
--- a/nhf/parts/box.py
+++ b/nhf/parts/box.py
@@ -87,7 +87,7 @@ class MountingBox(Model):
             diam = hole.diam if hole.diam else self.hole_diam
             result.push([(hole.x, hole.y)]).circle(diam / 2, mode='s')
         if self.profile_callback:
-            profile = self.profile_callback(profile)
+            result = self.profile_callback(result)
         return result
 
     def generate(self) -> Cq.Workplane:
@@ -108,20 +108,22 @@ class MountingBox(Model):
                 reverse_plane.moveTo(hole.x, hole.y).tagPlane(hole.rev_tag, '-Z')
 
         if self.generate_side_tags:
-            if self.centre_left_right_tags:
-                result.faces("<Y").workplane(origin=result.edges("<Y and >Z").val().Center()).tagPlane("left")
-                result.faces(">Y").workplane(origin=result.edges(">Y and >Z").val().Center()).tagPlane("right")
-            else:
-                result.faces("<Y").workplane(origin=result.vertices("<X and <Y and >Z").val().Center()).tagPlane("left")
-                result.faces(">Y").workplane(origin=result.vertices("<X and >Y and >Z").val().Center()).tagPlane("right")
+            xn, xp = 0, self.length
+            if self.centred[0]:
+                xn -= self.length/2
+                xp -= self.length/2
+            yn, yp = 0, self.width
+            if self.centred[1]:
+                yn -= self.width/2
+                yp -= self.width/2
 
-            c_y = ">Y" if self.flip_y else "<Y"
-            if self.centre_bot_top_tags:
-                result.faces("<X").workplane(origin=result.edges(f"<X and >Z").val().Center()).tagPlane("bot")
-                result.faces(">X").workplane(origin=result.edges(f">X and >Z").val().Center()).tagPlane("top")
-            else:
-                result.faces("<X").workplane(origin=result.vertices(f"<X and {c_y} and >Z").val().Center()).tagPlane("bot")
-                result.faces(">X").workplane(origin=result.vertices(f">X and {c_y} and >Z").val().Center()).tagPlane("top")
+            tag_x = xn + (self.length/2 if self.centre_left_right_tags else 0)
+            result.copyWorkplane(Cq.Workplane('XZ', origin=(tag_x, yn, self.thickness))).tagPlane("left")
+            result.copyWorkplane(Cq.Workplane('ZX', origin=(tag_x, yp, self.thickness))).tagPlane("right")
+
+            tag_y = yn + (self.width/2 if self.centre_bot_top_tags else 0)
+            result.copyWorkplane(Cq.Workplane('ZY', origin=(xn, tag_y, self.thickness))).tagPlane("bot")
+            result.copyWorkplane(Cq.Workplane('YZ', origin=(xp, tag_y, self.thickness))).tagPlane("top")
             result.faces(">Z").tag("dir")
         return result
 
diff --git a/nhf/touhou/houjuu_nue/wing.py b/nhf/touhou/houjuu_nue/wing.py
index 1032772..0da6fd3 100644
--- a/nhf/touhou/houjuu_nue/wing.py
+++ b/nhf/touhou/houjuu_nue/wing.py
@@ -577,6 +577,17 @@ class WingProfile(Model):
             Hole(sign * x, tag=tag)
             for x, tag in joint.hole_loc_tags()
         ]
+        def carve_sides(profile):
+            dy = (segment_thickness + joint.total_thickness) / 4
+            return (
+                profile
+                .push([(0,-dy), (0,dy)])
+                .rect(
+                    joint.parent_arm_width,
+                    (segment_thickness - joint.total_thickness) / 2,
+                    mode='s',
+                )
+            )
         # FIXME: Carve out the sides so light can pass through
         mbox = MountingBox(
             length=joint.lip_length,
@@ -586,6 +597,7 @@ class WingProfile(Model):
             hole_diam=joint.hole_diam,
             centred=(True, True),
             centre_left_right_tags=True,
+            profile_callback=carve_sides,
         )
         return mbox