diff --git a/opel_pin.py b/opel_pin.py
index 2114377..54ac824 100644
--- a/opel_pin.py
+++ b/opel_pin.py
@@ -4,28 +4,56 @@ from ocp_vscode import show
 # ==========================================
 # --- MASTER PARAMETERS ---
 model_size = 31.0  # Outer diameter of the ring
-overhang = model_size * (3.0 / model_size)     # How many mm the bolt sticks out past the ring
+overhang = model_size * (3.0 / 31.0)     # How many mm the bolt sticks out
 # ==========================================
 
 # --- Derived Parameters ---
 outer_diameter = model_size
-inner_diameter = model_size * (25.4 / model_size)
-thickness      = model_size * (2.3 / model_size)
+inner_diameter = model_size * (25.4 / 31.0)
+thickness      = model_size * (2.3 / 31.0)
 
-pin_diameter   = model_size * (3.1 / model_size)
-pin_length     = model_size * (10.8 / model_size)
-pin_spacing    = model_size * (14.0 / model_size)
-pin_height_offset = model_size * (1.55 / model_size)
-fillet_radius  = model_size * (0.15 / model_size)
+pin_diameter   = model_size * (3.1 / 31.0)
+pin_length     = model_size * (10.8 / 31.0)
+pin_spacing    = model_size * (14.0 / 31.0)
+pin_height_offset = model_size * (1.55 / 31.0)
+fillet_radius  = model_size * (0.15 / 31.0)
+
+# --- Stud Parameters ---
+stud_stickout  = model_size * (0.4 / 31.0)
+stud_thickness = model_size * (0.5 / 31.0)
 
 # --- Lightning Bolt Proportions ---
 W = (outer_diameter / 2) + overhang
 bound = model_size 
-H_outer = model_size * (3.1 / model_size) 
-H_inner = model_size * (0.5 / model_size)
-X_point = model_size * (5.8 / model_size)
-X_inner = model_size * (2.7 / model_size)
+H_outer = model_size * (3.1 / 31.0) 
+H_inner = model_size * (0.5 / 31.0)
+X_point = model_size * (5.8 / 31.0)
+X_inner = model_size * (2.7 / 31.0)
 
+# ==========================================
+# --- 1. BUILD THE MASTER PIN ---
+# We build a single fully-studded pin first.
+with BuildPart() as master_pin:
+    # Build the smooth base cylinder
+    Cylinder(radius=pin_diameter / 2, height=pin_length)
+    
+    # We will place 3 rows of studs vertically along the pin
+    # We use 0.25 and -0.25 so the studs sit neatly along the middle shaft
+    z_offsets = [pin_length * 0.25, 0, -pin_length * 0.25]
+    
+    for z in z_offsets:
+        with Locations((0, 0, z)):
+            # PolarLocations places local coordinate systems around a circle.
+            # It naturally rotates so the local "X" axis points directly outward!
+            with PolarLocations(radius=pin_diameter / 2, count=4):
+                # A box is drawn. Since we want it sticking out by "stud_stickout",
+                # we make its length exactly double that (half embeds into the pin, half sticks out)
+                Box(length=stud_stickout * 2, width=stud_thickness, height=stud_thickness)
+# ==========================================
+
+
+# ==========================================
+# --- 2. BUILD THE OPEL LOGO ---
 with BuildPart() as opel_pin:
     # 1. Base Ring
     with BuildSketch() as ring_sketch:
@@ -36,47 +64,33 @@ with BuildPart() as opel_pin:
     # 2. Lightning Bolt Profile (Aggressive Z-Shape)
     with BuildSketch() as bolt_sketch:
         pts = [
-            (-bound, H_outer),           # 1. Top-left outer edge
-            (-bound, -H_inner),          # 2. Bottom-left outer edge of upper bar
-            (-X_inner, -H_inner),        # 3. Inner bottom corner (cuts right, past center)
-            (-X_point, -H_outer),        # 4. Sharp bottom-left point (diagonals back left)
-            (bound, -H_outer),           # 5. Bottom-right outer edge
-            (bound, H_inner),            # 6. Top-right outer edge of lower bar
-            (X_inner, H_inner),          # 7. Inner top corner (cuts left, past center)
-            (X_point, H_outer)           # 8. Sharp top-right point (diagonals back right)
+            (-bound, H_outer),           
+            (-bound, -H_inner),          
+            (-X_inner, -H_inner),        
+            (-X_point, -H_outer),        
+            (bound, -H_outer),           
+            (bound, H_inner),            
+            (X_inner, H_inner),          
+            (X_point, H_outer)           
         ]
         z_shape = Polygon(*pts)
-
-        # Fillet the 2D corners of the Z shape so the inner zig-zag isn't infinitely sharp
         fillet(z_shape.vertices(), radius=fillet_radius)
-        
-        # Cleanly slice off the overhangs
         Circle(W, mode=Mode.INTERSECT)
     extrude(amount=thickness)
 
-    # ==========================================
-    # ---> THE FIX: Fillet ALL top edges <---
-    # 1. Grab the highest face on the Z-axis (the newly merged face of both ring + bolt)
+    # 3. Fillet ALL top edges
     top_face = opel_pin.faces().sort_by(Axis.Z)[-1]
-    
-    # 2. Grab ALL edges of that top face (no filtering)
-    all_top_edges = top_face.edges()
-    
-    # 3. Apply the 3D fillet to the entire border
-    fillet(all_top_edges, radius=fillet_radius)
-    # ==========================================
+    fillet(top_face.edges(), radius=fillet_radius)
 
-    # 3. Mounting Pins (on the back face)
-    bottom_face = opel_pin.faces().sort_by(Axis.Z)[0]
-    
-    with BuildSketch(bottom_face) as pin_sketch:
-        with Locations((-pin_spacing, -pin_height_offset), (pin_spacing, pin_height_offset)):
-            Circle(pin_diameter / 2)
-            
-    extrude(amount=pin_length)
+    # 4. Attach the Studded Mounting Pins
+    # Because the logo extrudes upwards from Z=0, the back is perfectly flat at Z=0.
+    # We place our master_pin so its top (pin_length / 2) sits flush against the back.
+    with Locations((-pin_spacing, pin_height_offset, -pin_length / 2), 
+                   (pin_spacing, -pin_height_offset, -pin_length / 2)):
+        add(master_pin.part)
+# ==========================================
 
 # --- Export for 3D Printing ---
-# This saves a STEP file in the same folder as your python script
 export_step(opel_pin.part, "vintage_opel_pin.step")
 
 # --- Send to OCP CAD Viewer ---