diff --git a/cad/build.py b/cad/build.py
index cc39096..a84b0f7 100644
--- a/cad/build.py
+++ b/cad/build.py
@@ -1,86 +1,90 @@
 # pyright: reportUnusedCallResult=false, reportWildcardImportFromLibrary=false
 from build123d import *
 
-bearing_offset = 20
-bearing_diameter = 22
-bearing_through_hole_diameter = 15
-bearing_height = 7
-shaft_clearance_diameter = 25
+def build_drive_shaft_mount():
+    bearing_offset = 20
+    bearing_diameter = 22
+    bearing_through_hole_diameter = 15
+    bearing_height = 7
+    shaft_clearance_diameter = 25
 
-core_width = 40
-thickness = 20
+    core_width = 40
+    thickness = 20
 
-screw_blocks_width = thickness
-screw_blocks_height = bearing_offset
-screw_blocks_radius = 3
+    screw_blocks_width = thickness
+    screw_blocks_height = bearing_offset
+    screw_blocks_radius = 3
 
-screw_head_diameter = 8.5
-screw_head_depth = 5
-screw_body_diameter = 5
+    screw_head_diameter = 8.5
+    screw_head_depth = 5
+    screw_body_diameter = 5
 
-track_width = 6.2
-track_height = 1.8
+    track_width = 6.2
+    track_height = 1.8
 
-assert (bearing_offset - bearing_diameter / 2) > 0
-assert (core_width - bearing_diameter) > 0
-assert (screw_blocks_width - (screw_blocks_radius * 2)) >= 0
-assert (bearing_offset - screw_blocks_height) >= 0
+    assert (bearing_offset - bearing_diameter / 2) > 0
+    assert (core_width - bearing_diameter) > 0
+    assert (screw_blocks_width - (screw_blocks_radius * 2)) >= 0
+    assert (bearing_offset - screw_blocks_height) >= 0
 
 
-with BuildPart() as drive_shaft_mount:
-    with BuildSketch() as sketch:
-        with BuildLine() as profile:
-            l1 = Line(
-                (0,0),
-                ((core_width / 2) + screw_blocks_width, 0)
-            )
+    with BuildPart() as drive_shaft_mount:
+        with BuildSketch():
+            with BuildLine() as profile:
+                l1 = Line(
+                    (0,0),
+                    ((core_width / 2) + screw_blocks_width, 0)
+                )
 
-            polyline_path = (
-                l1 @ 1,
-                ((l1 @ 1).X, screw_blocks_height),
-                (core_width / 2, screw_blocks_height),
-            )
-            match (float)(bearing_offset - screw_blocks_height):
-                case 0:
-                    FilletPolyline(
-                        *polyline_path,
-                        radius=screw_blocks_radius
-                    )
-                case len if len > 0 and len < screw_blocks_radius:
-                    sbl = FilletPolyline(
-                        *polyline_path,
-                        radius=screw_blocks_radius
-                    )
-                    Line(
-                        sbl @ 1,
-                        ((sbl @ 1).X, bearing_offset)
-                    )
-                case len if len >= screw_blocks_radius:
-                    FilletPolyline(
-                        *polyline_path,
-                        (core_width / 2, bearing_offset),
-                        radius=screw_blocks_radius
-                    )
-                case _: assert False
+                polyline_path = (
+                    l1 @ 1,
+                    ((l1 @ 1).X, screw_blocks_height),
+                    (core_width / 2, screw_blocks_height),
+                )
+                match (float)(bearing_offset - screw_blocks_height):
+                    case 0:
+                        FilletPolyline(
+                            *polyline_path,
+                            radius=screw_blocks_radius
+                        )
+                    case len if len > 0 and len < screw_blocks_radius:
+                        sbl = FilletPolyline(
+                            *polyline_path,
+                            radius=screw_blocks_radius
+                        )
+                        Line(
+                            sbl @ 1,
+                            ((sbl @ 1).X, bearing_offset)
+                        )
+                    case len if len >= screw_blocks_radius:
+                        FilletPolyline(
+                            *polyline_path,
+                            (core_width / 2, bearing_offset),
+                            radius=screw_blocks_radius
+                        )
+                    case _: assert False
 
-            CenterArc((0, bearing_offset), core_width / 2, 90, -90)
-            mirror(profile.line, Plane.YZ)
-        make_face()
+                CenterArc((0, bearing_offset), core_width / 2, 90, -90)
+                mirror(profile.line, Plane.YZ)
+            make_face()
 
-        with Locations((0, bearing_offset)):
-            Circle(bearing_through_hole_diameter / 2, mode=Mode.SUBTRACT)
+            with Locations((0, bearing_offset)):
+                Circle(bearing_through_hole_diameter / 2, mode=Mode.SUBTRACT)
 
-    extrude(amount=thickness / 2)
-    mirror(about=Plane.XY)
+        extrude(amount=thickness / 2)
+        mirror(about=Plane.XY)
 
-    with Locations((0, bearing_offset, drive_shaft_mount.faces().sort_by(Axis.Z)[-1].center().Z)):
-        Hole(bearing_diameter / 2, (thickness / 2) + (bearing_height / 2))
-        Hole(shaft_clearance_diameter / 2, (thickness / 2) - (bearing_height / 2))
+        with Locations((0, bearing_offset, drive_shaft_mount.faces().sort_by(Axis.Z)[-1].center().Z)):
+            Hole(bearing_diameter / 2, (thickness / 2) + (bearing_height / 2))
+            Hole(shaft_clearance_diameter / 2, (thickness / 2) - (bearing_height / 2))
 
-    Box(core_width + (screw_blocks_width * 2), track_width, track_height, (90, 0, 0), (Align.CENTER, Align.CENTER, Align.MIN))
+        Box(core_width + (screw_blocks_width * 2), track_width, track_height, (90, 0, 0), (Align.CENTER, Align.CENTER, Align.MIN))
 
-    with Locations(drive_shaft_mount.faces().filter_by(Plane.XZ).sort_by(Axis.Y)[-2:]):
-        CounterBoreHole(screw_body_diameter / 2, screw_head_diameter / 2, screw_head_depth)
+        with Locations(drive_shaft_mount.faces().filter_by(Plane.XZ).sort_by(Axis.Y)[-2:]):
+            CounterBoreHole(screw_body_diameter / 2, screw_head_diameter / 2, screw_head_depth)
 
+    return drive_shaft_mount
+
+drive_shaft_mount = build_drive_shaft_mount()
 assert drive_shaft_mount.part is not None
 export_step(drive_shaft_mount.part, "drive shaft mount.step")