diff --git a/cad/build.py b/cad/build.py
index 14adf63..fe93a44 100644
--- a/cad/build.py
+++ b/cad/build.py
@@ -4,7 +4,8 @@ from build123d import *
 bearing_offset = 20
 bearing_diameter = 22
 bearing_through_hole_diameter = 15
-bearing_height = 8
+bearing_height = 7
+shaft_clearance_diameter = 25
 
 core_width = 40
 thickness = 20
@@ -73,7 +74,8 @@ with BuildPart() as builder:
     mirror(about=Plane.XY)
 
     with Locations((0, bearing_offset, builder.faces().sort_by(Axis.Z)[-1].center().Z)):
-        Hole(bearing_diameter / 2, bearing_height)
+        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))