nhf/parts/fasteners.py

@@ -122,5 +122,5 @@ class HexNut(Item):
         )
         result.faces("<Z").tag("bot")
         result.faces(">Z").tag("top")
-        result.copyWorkplane(Cq.Workplane('XY')).tagPlane("dir", direction="+X")
+        result.copyWorkplane(Cq.Workplane('XY')).tagPlane("dirX", direction="+X")
         return result

nhf/touhou/houjuu_nue/__init__.py

@@ -77,22 +77,15 @@ class Parameters(Model):
 
     def __post_init__(self):
         super().__init__(name="houjuu-nue")
-        self.wing_r1.base_joint = self.harness.hs_hirth_joint
-        self.wing_r2.base_joint = self.harness.hs_hirth_joint
-        self.wing_r3.base_joint = self.harness.hs_hirth_joint
-        self.wing_l1.base_joint = self.harness.hs_hirth_joint
-        self.wing_l2.base_joint = self.harness.hs_hirth_joint
-        self.wing_l3.base_joint = self.harness.hs_hirth_joint
+        self.wing_r1.root_joint = self.harness.root_joint
+        self.wing_r2.root_joint = self.harness.root_joint
+        self.wing_r3.root_joint = self.harness.root_joint
+        self.wing_l1.root_joint = self.harness.root_joint
+        self.wing_l2.root_joint = self.harness.root_joint
+        self.wing_l3.root_joint = self.harness.root_joint
 
         self.wing_r1.shoulder_joint.torsion_joint
 
-        assert self.wing_r1.hs_joint_axis_diam == self.harness.hs_joint_axis_diam
-        assert self.wing_r2.hs_joint_axis_diam == self.harness.hs_joint_axis_diam
-        assert self.wing_r3.hs_joint_axis_diam == self.harness.hs_joint_axis_diam
-        assert self.wing_l1.hs_joint_axis_diam == self.harness.hs_joint_axis_diam
-        assert self.wing_l2.hs_joint_axis_diam == self.harness.hs_joint_axis_diam
-        assert self.wing_l3.hs_joint_axis_diam == self.harness.hs_joint_axis_diam
-
     @submodel(name="harness")
     def submodel_harness(self) -> Model:
         return self.harness
@@ -126,19 +119,20 @@ class Parameters(Model):
         result = (
             Cq.Assembly()
             .add(self.harness.assembly(), name="harness", loc=Cq.Location((0, 0, 0)))
-            .add(self.wing_r1.assembly(parts, **kwargs), name="wing_r1")
-            .add(self.wing_r2.assembly(parts, **kwargs), name="wing_r2")
-            .add(self.wing_r3.assembly(parts, **kwargs), name="wing_r3")
-            .add(self.wing_l1.assembly(parts, **kwargs), name="wing_l1")
-            .add(self.wing_l2.assembly(parts, **kwargs), name="wing_l2")
-            .add(self.wing_l3.assembly(parts, **kwargs), name="wing_l3")
+            .add(self.wing_r1.assembly(parts, root_offset=9, **kwargs), name="wing_r1")
+            .add(self.wing_r2.assembly(parts, root_offset=7, **kwargs), name="wing_r2")
+            .add(self.wing_r3.assembly(parts, root_offset=6, **kwargs), name="wing_r3")
+            .add(self.wing_l1.assembly(parts, root_offset=7, **kwargs), name="wing_l1")
+            .add(self.wing_l2.assembly(parts, root_offset=8, **kwargs), name="wing_l2")
+            .add(self.wing_l3.assembly(parts, root_offset=9, **kwargs), name="wing_l3")
         )
-        for tag, offset in [("r1", 9), ("r2", 7), ("r3", 6), ("l1", 7), ("l2", 8), ("l3", 9)]:
-            self.harness.hs_hirth_joint.add_constraints(
+        for tag in ["r1", "r2", "r3", "l1", "l2", "l3"]:
+            self.harness.add_root_joint_constraint(
                 result,
-                f"harness/{tag}",
-                f"wing_{tag}/s0/hs",
-                offset=offset)
+                "harness/base",
+                f"wing_{tag}/root",
+                tag
+            )
         return result.solve()
 
     @submodel(name="trident")

nhf/touhou/houjuu_nue/harness.py

@@ -2,7 +2,8 @@ from dataclasses import dataclass, field
 import cadquery as Cq
 from nhf.parts.joints import HirthJoint
 from nhf import Material, Role
-from nhf.build import Model, TargetKind, target, assembly
+from nhf.build import Model, TargetKind, target, assembly, submodel
+from nhf.touhou.houjuu_nue.joints import RootJoint
 import nhf.utils
 
 @dataclass(frozen=True, kw_only=True)
@@ -63,33 +64,18 @@ class Harness(Model):
         ("r3", BASE_POS_X, -BASE_POS_Y),
         ("l3", -BASE_POS_X, -BASE_POS_Y),
     ])
-    # Holes drilled onto harness for attachment with HS joint
-    harness_to_root_conn_diam: float = 6
 
-    hs_hirth_joint: HirthJoint = field(default_factory=lambda: HirthJoint(
-        radius=25.0,
-        radius_inner=15.0,
-        tooth_height=7.0,
-        base_height=5.0,
-        n_tooth=24,
-    ))
-
-    hs_joint_base_width: float = 85
-    hs_joint_base_thickness: float = 10
-    hs_joint_corner_fillet: float = 5
-    hs_joint_corner_cbore_diam: float = 12
-    hs_joint_corner_cbore_depth: float = 2
-    hs_joint_corner_inset: float = 12
-
-    hs_joint_axis_diam: float = 12.0
-    hs_joint_axis_cbore_diam: float = 20
-    hs_joint_axis_cbore_depth: float = 3
+    root_joint: RootJoint = field(default_factory=lambda: RootJoint())
 
     mannequin: Mannequin = Mannequin()
 
     def __post_init__(self):
         super().__init__(name="harness")
 
+    @submodel(name="root-joint")
+    def submodel_root_joint(self) -> Model:
+        return self.root_joint
+
     @target(name="profile", kind=TargetKind.DXF)
     def profile(self) -> Cq.Sketch:
         """
@@ -115,12 +101,12 @@ class Harness(Model):
             .fillet(self.fillet)
         )
         for tag, x, y in self.wing_base_pos:
-            conn = [(px + x, py + y) for px, py in self.hs_joint_harness_conn()]
+            conn = [(px + x, py + y) for px, py in self.root_joint.corner_pos()]
             sketch = (
                 sketch
                 .push(conn)
                 .tag(tag)
-                .circle(self.harness_to_root_conn_diam / 2, mode='s')
+                .circle(self.root_joint.corner_hole_diam / 2, mode='s')
                 .reset()
             )
         return sketch
@@ -138,78 +124,27 @@ class Harness(Model):
         plane = result.faces(">Y").workplane()
         for tag, x, y in self.wing_base_pos:
             conn = [(px + x, py + y) for px, py
-                    in self.hs_joint_harness_conn()]
+                    in self.root_joint.corner_pos()]
             for i, (px, py) in enumerate(conn):
                 plane.moveTo(px, py).tagPoint(f"{tag}_{i}")
         return result
 
-    def hs_joint_harness_conn(self) -> list[tuple[int, int]]:
-        """
-        Generates a set of points corresponding to the connectorss
-        """
-        dx = self.hs_joint_base_width / 2 - self.hs_joint_corner_inset
-        return [
-            (dx, dx),
-            (dx, -dx),
-            (-dx, -dx),
-            (-dx, dx),
-        ]
+    def add_root_joint_constraint(
+            self,
+            a: Cq.Assembly,
+            harness_tag: str,
+            joint_tag: str,
+            mount_tag: str):
+        for i in range(4):
+            a.constrain(f"{harness_tag}?{mount_tag}_{i}", f"{joint_tag}/parent?h{i}", "Point")
 
-    @target(name="hs-joint-parent")
-    def hs_joint_parent(self):
-        """
-        Parent part of the Houjuu-Scarlett joint, which is composed of a Hirth
-        coupling, a cylindrical base, and a mounting base.
-        """
-        hirth = self.hs_hirth_joint.generate()
-        conn = self.hs_joint_harness_conn()
-        result = (
-            Cq.Workplane('XY')
-            .box(
-                self.hs_joint_base_width,
-                self.hs_joint_base_width,
-                self.hs_joint_base_thickness,
-                centered=(True, True, False))
-            .translate((0, 0, -self.hs_joint_base_thickness))
-            .edges("|Z")
-            .fillet(self.hs_joint_corner_fillet)
-            .faces(">Z")
-            .workplane()
-            .pushPoints(conn)
-            .cboreHole(
-                diameter=self.harness_to_root_conn_diam,
-                cboreDiameter=self.hs_joint_corner_cbore_diam,
-                cboreDepth=self.hs_joint_corner_cbore_depth)
-        )
-        # Creates a plane parallel to the holes but shifted to the base
-        plane = result.faces(">Z").workplane(offset=-self.hs_joint_base_thickness)
-
-        for i, (px, py) in enumerate(conn):
-            plane.moveTo(px, py).tagPoint(f"h{i}")
-        result = (
-            result
-            .faces(">Z")
-            .workplane()
-            .union(hirth, tol=0.1)
-            .clean()
-        )
-        result = (
-            result.faces("<Z")
-            .workplane()
-            .cboreHole(
-                diameter=self.hs_joint_axis_diam,
-                cboreDiameter=self.hs_joint_axis_cbore_diam,
-                cboreDepth=self.hs_joint_axis_cbore_depth,
-            )
-            .clean()
-        )
-        result.faces("<Z").tag("base")
-        return result
 
     @assembly()
-    def assembly(self) -> Cq.Assembly:
+    def assembly(self, with_root_joint: bool = False) -> Cq.Assembly:
         harness = self.surface()
         mannequin_z = self.mannequin.shoulder_to_waist * 0.6
+
+
         result = (
             Cq.Assembly()
             .addS(
@@ -224,13 +159,12 @@ class Harness(Model):
                 loc=Cq.Location((0, -self.thickness, -mannequin_z), (0, 0, 1), 180))
             .constrain("mannequin", "Fixed")
         )
-        for name in ["l1", "l2", "l3", "r1", "r2", "r3"]:
-            j = self.hs_joint_parent()
-            result.addS(
-                j, name=name,
-                role=Role.PARENT,
-                material=Material.PLASTIC_PLA)
-            for i in range(4):
-                result.constrain(f"base?{name}_{i}", f"{name}?h{i}", "Point")
+        if with_root_joint:
+            for name in ["l1", "l2", "l3", "r1", "r2", "r3"]:
+                result.addS(
+                    self.root_joint.assembly(), name=name,
+                    role=Role.PARENT,
+                    material=Material.PLASTIC_PLA)
+                self.add_root_joint_constraint(result, "base", name, name)
         result.solve()
         return result

nhf/touhou/houjuu_nue/joints.py

@@ -5,13 +5,204 @@ import cadquery as Cq
 from nhf import Material, Role
 from nhf.build import Model, target, assembly
 from nhf.parts.springs import TorsionSpring
-from nhf.parts.fasteners import FlatHeadBolt
-from nhf.parts.joints import TorsionJoint
+from nhf.parts.fasteners import FlatHeadBolt, HexNut, ThreaddedKnob
+from nhf.parts.joints import TorsionJoint, HirthJoint
 from nhf.parts.box import Hole, MountingBox, box_with_centre_holes
 import nhf.utils
 
 TOL = 1e-6
 
+@dataclass
+class RootJoint(Model):
+    """
+    The Houjuu-Scarlett Mechanism
+    """
+    knob: ThreaddedKnob = ThreaddedKnob(
+        mass=float('nan'),
+        diam_thread=12.0,
+        height_thread=30.0,
+        diam_knob=50.0,
+        # FIXME: Undetermined
+        diam_neck=30.0,
+        height_neck=10.0,
+        height_knob=10.0,
+    )
+    hex_nut: HexNut = HexNut(
+        # FIXME: Undetermined
+        mass=float('nan'),
+
+        diam_thread=12.0,
+        pitch=1.75,
+        thickness=9.8,
+        width=18.9,
+    )
+    hirth_joint: HirthJoint = field(default_factory=lambda: HirthJoint(
+        radius=25.0,
+        radius_inner=15.0,
+        tooth_height=7.0,
+        base_height=5.0,
+        n_tooth=24,
+    ))
+    parent_width: float = 85
+    parent_thickness: float = 10
+    parent_corner_fillet: float = 5
+    parent_corner_cbore_diam: float = 12
+    parent_corner_cbore_depth: float = 2
+    parent_corner_inset: float = 12
+    parent_mount_thickness: float = 25.4 / 16
+
+    child_corner_dx: float = 17.0
+    child_corner_dz: float = 24.0
+
+    axis_diam: float = 12.0
+    axis_cbore_diam: float = 20
+    axis_cbore_depth: float = 3
+    corner_hole_diam: float = 6.0
+
+    child_height: float = 60.0
+    child_width: float = 50.0
+    child_mount_thickness: float = 25.4 / 8
+
+    def corner_pos(self) -> list[tuple[int, int]]:
+        """
+        Generates a set of points corresponding to the connectorss
+        """
+        dx = self.parent_width / 2 - self.parent_corner_inset
+        return [
+            (dx, dx),
+            (dx, -dx),
+            (-dx, -dx),
+            (-dx, dx),
+        ]
+
+    @property
+    def total_height(self) -> float:
+        return self.parent_thickness + self.hirth_joint.total_height
+
+    @target(name="parent")
+    def parent(self):
+        """
+        Parent part of the Houjuu-Scarlett joint, which is composed of a Hirth
+        coupling, a cylindrical base, and a mounting base.
+        """
+        hirth = self.hirth_joint.generate()
+        conn = self.corner_pos()
+        result = (
+            Cq.Workplane('XY')
+            .box(
+                self.parent_width,
+                self.parent_width,
+                self.parent_thickness,
+                centered=(True, True, False))
+            .translate((0, 0, -self.parent_thickness))
+            .edges("|Z")
+            .fillet(self.parent_corner_fillet)
+            .faces(">Z")
+            .workplane()
+            .pushPoints(conn)
+            .cboreHole(
+                diameter=self.corner_hole_diam,
+                cboreDiameter=self.parent_corner_cbore_diam,
+                cboreDepth=self.parent_corner_cbore_depth)
+        )
+        # Creates a plane parallel to the holes but shifted to the base
+        plane = result.faces(">Z").workplane(offset=-self.parent_thickness)
+
+        for i, (px, py) in enumerate(conn):
+            plane.moveTo(px, py).tagPoint(f"h{i}")
+        result = (
+            result
+            .faces(">Z")
+            .workplane()
+            .union(hirth, tol=0.1)
+            .clean()
+        )
+        result = (
+            result.faces("<Z")
+            .workplane()
+            .hole(diameter=self.axis_diam)
+            .cut(self.hex_nut.generate().translate((0, 0, -self.parent_thickness)))
+        )
+        result.faces("<Z").tag("base")
+        return result
+
+    @target(name="child")
+    def child(self) -> Cq.Workplane:
+        hirth = self.hirth_joint.generate(is_mated=True)
+        dy = self.child_corner_dx
+        dx = self.child_corner_dz
+        conn = [
+            (-dx, -dy),
+            (dx, -dy),
+            (dx, dy),
+            (-dx, dy),
+        ]
+        result = (
+            Cq.Workplane('XY')
+            .box(
+                self.child_height,
+                self.child_width,
+                self.hirth_joint.base_height,
+                centered=(True, True, False))
+            #.translate((0, 0, -self.base_joint.base_height))
+            #.edges("|Z")
+            #.fillet(self.hs_joint_corner_fillet)
+            .faces(">Z")
+            .workplane()
+            .pushPoints(conn)
+            .hole(self.corner_hole_diam)
+        )
+        # Creates a plane parallel to the holes but shifted to the base
+        plane = result.faces(">Z").workplane(offset=-self.hirth_joint.base_height)
+
+        for i, (px, py) in enumerate(conn):
+            plane.moveTo(px, py).tagPlane(f"conn{i}")
+        result = (
+            result
+            .faces(">Z")
+            .workplane()
+            .union(hirth, tol=0.1)
+            .clean()
+        )
+        result = (
+            result.faces("<Z")
+            .workplane()
+            .hole(self.axis_diam)
+        )
+        return result
+
+    def assembly(self,
+                 offset: int = 0,
+                 fastener_pos: float = 0) -> Cq.Assembly:
+        """
+        Specify knob position to determine the position of the knob from fully
+        inserted (0) or fully uninserted (1)
+        """
+        knob_h = self.total_height + self.child_mount_thickness
+        result = (
+            Cq.Assembly()
+            .addS(self.parent(), name="parent",
+                  material=Material.PLASTIC_PLA,
+                  role=Role.PARENT)
+            .constrain("parent", "Fixed")
+            .addS(self.child(), name="child",
+                  material=Material.PLASTIC_PLA,
+                  role=Role.CHILD)
+            .addS(self.hex_nut.assembly(), name="hex_nut")
+            .addS(self.knob.assembly(), name="knob",
+                  loc=Cq.Location((0, 0, knob_h * fastener_pos)))
+            .constrain("knob/thread", "Fixed")
+            .constrain("hex_nut?bot", "parent?base", "Plane", param=0)
+            .constrain("hex_nut?dirX", "parent@faces@>X", "Axis", param=0)
+        )
+        self.hirth_joint.add_constraints(
+            result,
+            "parent",
+            "child",
+            offset=offset
+        )
+        return result.solve()
+
 @dataclass
 class ShoulderJoint(Model):
 
@@ -228,10 +419,11 @@ class ShoulderJoint(Model):
         return result
 
     @assembly()
-    def assembly(self, deflection: float = 0) -> Cq.Assembly:
+    def assembly(self, fastener_pos: float = 0.0, deflection: float = 0) -> Cq.Assembly:
         directrix = self.directrix_id
         mat = Material.RESIN_TRANSPERENT
         mat_spring = Material.STEEL_SPRING
+        bolt_z = self.height / 2 + self.bolt.height_thread * (fastener_pos - 1)
         result = (
             Cq.Assembly()
             .addS(self.child(), name="child",
@@ -239,18 +431,21 @@ class ShoulderJoint(Model):
             .constrain("child/core", "Fixed")
             .addS(self.torsion_joint.spring.generate(deflection=-deflection), name="spring_top",
                   role=Role.DAMPING, material=mat_spring)
-            .addS(self.bolt.assembly(), name="bolt_top")
             .addS(self.parent_top(),
                   name="parent_top",
                   role=Role.PARENT, material=mat)
             .addS(self.torsion_joint.spring.generate(deflection=deflection), name="spring_bot",
                   role=Role.DAMPING, material=mat_spring)
-            .addS(self.bolt.assembly(), name="bolt_bot")
             .addS(self.parent_bot(),
                   name="parent_bot",
                   role=Role.PARENT, material=mat)
-            .constrain("bolt_top/thread?root", "parent_top/track?bot", "Plane", param=0)
-            .constrain("bolt_bot/thread?root", "parent_bot/track?bot", "Plane", param=0)
+            # Fasteners
+            .addS(self.bolt.assembly(), name="bolt_top",
+                  loc=Cq.Location((0, 0, bolt_z)))
+            .constrain("bolt_top/thread?root", 'Fixed')
+            .addS(self.bolt.assembly(), name="bolt_bot",
+                  loc=Cq.Location((0, 0, -bolt_z), (1,0,0), 180))
+            .constrain("bolt_bot/thread?root", 'Fixed')
         )
         TorsionJoint.add_constraints(
             result,

nhf/touhou/houjuu_nue/wing.py

@@ -11,7 +11,7 @@ from nhf import Material, Role
 from nhf.build import Model, TargetKind, target, assembly, submodel
 from nhf.parts.box import box_with_centre_holes, MountingBox, Hole
 from nhf.parts.joints import HirthJoint
-from nhf.touhou.houjuu_nue.joints import ShoulderJoint, ElbowJoint, DiskJoint
+from nhf.touhou.houjuu_nue.joints import RootJoint, ShoulderJoint, ElbowJoint, DiskJoint
 from nhf.parts.planar import extrude_with_markers
 import nhf.utils
 
@@ -20,19 +20,8 @@ class WingProfile(Model):
 
     name: str = "wing"
 
-    base_joint: HirthJoint = field(default_factory=lambda: HirthJoint(
-        radius=25.0,
-        radius_inner=15.0,
-        tooth_height=7.0,
-        base_height=5,
-        n_tooth=24,
-    ))
+    root_joint: RootJoint = field(default_factory=lambda: RootJoint())
     base_width: float = 80.0
-    hs_joint_corner_dx: float = 17.0
-    hs_joint_corner_dz: float = 24.0
-    hs_joint_corner_hole_diam: float = 6.0
-    hs_joint_axis_diam: float = 12.0
-    base_plate_width: float = 50.0
 
     panel_thickness: float = 25.4 / 16
     spacer_thickness: float = 25.4 / 8
@@ -108,6 +97,8 @@ class WingProfile(Model):
         self.shoulder_joint.angle_neutral = -self.shoulder_angle_neutral - self.shoulder_angle_bias
         self.shoulder_axle_loc = Cq.Location.from2d(self.shoulder_tip_x, self.shoulder_tip_y - self.shoulder_width / 2, -self.shoulder_angle_bias)
 
+        assert self.spacer_thickness == self.root_joint.child_mount_thickness
+
     @submodel(name="shoulder-joint")
     def submodel_shoulder_joint(self) -> Model:
         return self.shoulder_joint
@@ -126,55 +117,6 @@ class WingProfile(Model):
     def shoulder_height(self) -> float:
         return self.shoulder_joint.height
 
-    @target(name="base-hs-joint")
-    def base_hs_joint(self) -> Cq.Workplane:
-        """
-        Parent part of the Houjuu-Scarlett joint, which is composed of a Hirth
-        coupling, a cylindrical base, and a mounting base.
-        """
-        hirth = self.base_joint.generate(is_mated=True)
-        dy = self.hs_joint_corner_dx
-        dx = self.hs_joint_corner_dz
-        conn = [
-            (-dx, -dy),
-            (dx, -dy),
-            (dx, dy),
-            (-dx, dy),
-        ]
-        result = (
-            Cq.Workplane('XY')
-            .box(
-                self.root_height,
-                self.base_plate_width,
-                self.base_joint.base_height,
-                centered=(True, True, False))
-            #.translate((0, 0, -self.base_joint.base_height))
-            #.edges("|Z")
-            #.fillet(self.hs_joint_corner_fillet)
-            .faces(">Z")
-            .workplane()
-            .pushPoints(conn)
-            .hole(self.hs_joint_corner_hole_diam)
-        )
-        # Creates a plane parallel to the holes but shifted to the base
-        plane = result.faces(">Z").workplane(offset=-self.base_joint.base_height)
-
-        for i, (px, py) in enumerate(conn):
-            plane.moveTo(px, py).tagPlane(f"conn{i}")
-        result = (
-            result
-            .faces(">Z")
-            .workplane()
-            .union(hirth, tol=0.1)
-            .clean()
-        )
-        result = (
-            result.faces("<Z")
-            .workplane()
-            .hole(self.hs_joint_axis_diam)
-        )
-        return result
-
     def outer_profile_s0(self) -> Cq.Sketch:
         """
         The outer boundary of s0, used to produce the curved panel and the
@@ -275,11 +217,11 @@ class WingProfile(Model):
         """
         Should be cut
         """
-        assert self.base_plate_width < self.base_width
-        assert self.hs_joint_corner_dx * 2 < self.base_width
-        assert self.hs_joint_corner_dz * 2 < self.root_height
-        dy = self.hs_joint_corner_dx
-        dx = self.hs_joint_corner_dz
+        assert self.root_joint.child_width < self.base_width
+        assert self.root_joint.child_corner_dx * 2 < self.base_width
+        assert self.root_joint.child_corner_dz * 2 < self.root_height
+        dy = self.root_joint.child_corner_dx
+        dx = self.root_joint.child_corner_dz
         holes = [
             Hole(x=-dx, y=-dy),
             Hole(x=dx, y=-dy),
@@ -288,17 +230,17 @@ class WingProfile(Model):
         ]
         return MountingBox(
             length=self.root_height,
-            width=self.base_plate_width,
+            width=self.root_joint.child_width,
             thickness=self.spacer_thickness,
             holes=holes,
-            hole_diam=self.hs_joint_corner_hole_diam,
+            hole_diam=self.root_joint.corner_hole_diam,
             centred=(True, True),
             flip_y=self.flip,
         )
 
     def surface_s0(self, top: bool = False) -> Cq.Workplane:
-        base_dx = -(self.base_width - self.base_plate_width) / 2
-        base_dy = self.base_joint.joint_height
+        base_dx = -(self.base_width - self.root_joint.child_width) / 2
+        base_dy = self.root_joint.hirth_joint.joint_height
         loc_tip = Cq.Location(0, -self.shoulder_joint.parent_lip_width / 2)
         tags = [
             ("shoulder",
@@ -351,14 +293,6 @@ class WingProfile(Model):
                 .constrain(f"{tag}?{top_tag}", f"top?{tag}", "Plane")
                 .constrain(f"{tag}?dir", f"top?{tag}_dir", "Axis")
             )
-        hs_joint = self.base_hs_joint()
-        (
-            result
-            .addS(hs_joint, name="hs", role=Role.CHILD, material=self.mat_hs_joint)
-            .constrain("hs?conn0", "base?conn0", "Plane", param=0)
-            .constrain("hs?conn1", "base?conn1", "Plane", param=0)
-            .constrain("hs?conn2", "base?conn2", "Plane", param=0)
-        )
         return result.solve()
 
 
@@ -627,9 +561,11 @@ class WingProfile(Model):
                  parts: Optional[list[str]] = None,
                  shoulder_deflection: float = 0.0,
                  elbow_wrist_deflection: float = 0.0,
+                 root_offset: int = 5,
+                 fastener_pos: float = 0.0,
                  ) -> Cq.Assembly():
         if parts is None:
-            parts = ["s0", "shoulder", "s1", "elbow", "s2", "wrist", "s3"]
+            parts = ["root", "s0", "shoulder", "s1", "elbow", "s2", "wrist", "s3"]
         result = (
             Cq.Assembly()
         )
@@ -639,8 +575,23 @@ class WingProfile(Model):
 
         if "s0" in parts:
             result.add(self.assembly_s0(), name="s0")
+        if "root" in parts:
+            result.addS(self.root_joint.assembly(
+                offset=root_offset,
+                fastener_pos=fastener_pos,
+            ), name="root")
+            result.constrain("root/parent", "Fixed")
+        if "s0" in parts and "root" in parts:
+            (
+                result
+                .constrain("s0/base?conn0", "root/child?conn0", "Plane", param=0)
+                .constrain("s0/base?conn1", "root/child?conn1", "Plane", param=0)
+                .constrain("s0/base?conn2", "root/child?conn2", "Plane", param=0)
+            )
         if "shoulder" in parts:
-            result.add(self.shoulder_joint.assembly(deflection=shoulder_deflection * 80), name="shoulder")
+            result.add(self.shoulder_joint.assembly(
+                fastener_pos=fastener_pos,
+                deflection=shoulder_deflection * 80), name="shoulder")
         if "s0" in parts and "shoulder" in parts:
             (
                 result