diff --git a/monitor/rear_mount.py b/monitor/rear_mount.py
index 4e3e732..8017de2 100644
--- a/monitor/rear_mount.py
+++ b/monitor/rear_mount.py
@@ -62,11 +62,11 @@ rear_mount = (
     .faces(">X")
     .workplane(centerOption="CenterOfBoundBox", offset=-(rear_mount_width-20)/2)
     .transformed(rotate=cq.Vector(0, 0, 90))
-    .center(-hinge_w / 2, rear_mount_thickness / 2).tag("hingeplane")
+    .center(-hinge_s / 2, rear_mount_thickness / 2).tag("hingeplane")
     .placeSketch(hinge_profile_1)
     .extrude(-hinge_t)
     .workplaneFromTagged("hingeplane")
-    .workplane(offset=-hinge_t - hinge_w)
+    .workplane(offset=-hinge_t - hinge_)
     .placeSketch(hinge_profile_2)
     .extrude(-hinge_t))
 
diff --git a/monitor/upper_arm.py b/monitor/upper_arm.py
new file mode 100644
index 0000000..e3208f3
--- /dev/null
+++ b/monitor/upper_arm.py
@@ -0,0 +1,60 @@
+# This is the arm from the tripod to the "elbow"
+
+import cadquery2 as cq
+from cadquery2 import exporters
+
+from hinge import hinge_gap, hinge_w, hinge_profile_1, hinge_profile_2, hinge_t
+
+# monitor hinge dimensions
+inner_monitor_hinge = 3.2 / 2
+outer_monitor_hinge = hinge_w / 2
+
+# tripod hinge dimensions
+inner_tripod_hinge = 7.5 / 2
+outer_tripod_hinge = 17.5 / 2
+tripod_hinge_width = 5.5
+
+
+monitor_hinge_shape = (
+    cq.Sketch().circle(outer_monitor_hinge).circle(inner_monitor_hinge, mode="s")
+)
+
+tripod_hinge_shape = (
+    cq.Sketch().circle(outer_tripod_hinge).circle(inner_tripod_hinge, mode="s")
+)
+
+arm_width = min(tripod_hinge_width, hinge_gap)
+arm_length = 150
+
+lower_arm = (
+    cq.Workplane("XY")
+    .rect(arm_width, arm_width)
+    .extrude(arm_length)
+    .edges("|Z or <Z or >Z")
+    .fillet(0.25)
+    .faces(">Y")
+    # Add hinge that connects to the monitor
+    .workplane(
+        centerOption="CenterOfBoundBox", offset=(hinge_gap - arm_width) / 2
+    )
+    .center(0, arm_length / 2 + (outer_monitor_hinge - inner_monitor_hinge))
+    .placeSketch(monitor_hinge_shape)
+    .extrude(-hinge_gap)
+    .center(0, -(arm_length + outer_tripod_hinge))
+    # Undo previous offset + new offset
+    .workplane(
+        offset=-(hinge_gap - arm_width - tripod_hinge_width + arm_width) / 2
+    )
+    # Add hinge that connects to the tripod
+    # Hinge integration
+    .transformed(rotate=cq.Vector(0, 0, 90))
+    .center(-hinge_w / 2, 0).tag("hingeplane")
+    .placeSketch(hinge_profile_1)
+    .extrude(-hinge_t)
+    .workplaneFromTagged("hingeplane")
+    .workplane(offset=-hinge_t - hinge_w)
+    .placeSketch(hinge_profile_2)
+    .extrude(-hinge_t)
+)
+
+exporters.export(lower_arm, "upper_arm.stl")