diff --git a/nhf/handle.py b/nhf/handle.py
index 36462b8..36c41a7 100644
--- a/nhf/handle.py
+++ b/nhf/handle.py
@@ -5,7 +5,7 @@ from dataclasses import dataclass
 import cadquery as Cq
 import nhf.metric_threads as NMt
 
-@dataclass(frozen=True)
+@dataclass
 class Handle:
     """
     Characteristic of a tool handle
diff --git a/nhf/joints.py b/nhf/joints.py
index 1fb938b..f8e5f8f 100644
--- a/nhf/joints.py
+++ b/nhf/joints.py
@@ -4,7 +4,7 @@ import cadquery as Cq
 import nhf.springs as NS
 from nhf import Role
 
-@dataclass(frozen=True)
+@dataclass
 class HirthJoint:
     """
     A Hirth joint attached to a cylindrical base
@@ -231,26 +231,26 @@ class TorsionJoint:
     """
 
     # Radius limit for rotating components
-    radius = 40
-    disk_height = 10
+    radius: float = 40
+    disk_height: float = 10
 
-    radius_spring = 15
-    radius_axle = 6
+    radius_spring: float = 15
+    radius_axle: float = 6
 
     # Offset of the spring hole w.r.t. surface
-    spring_hole_depth = 4
+    spring_hole_depth: float = 4
 
     # Also used for the height of the hole for the spring
-    spring_thickness = 2
-    spring_height = 15
+    spring_thickness: float = 2
+    spring_height: float = 15
 
-    spring_tail_length = 40
+    spring_tail_length: float = 40
 
-    groove_radius_outer = 35
-    groove_radius_inner = 20
-    groove_depth = 5
-    rider_gap = 2
-    n_slots = 8
+    groove_radius_outer: float = 35
+    groove_radius_inner: float = 20
+    groove_depth: float = 5
+    rider_gap: float = 2
+    n_slots: float = 8
 
     right_handed: bool = False
 
diff --git a/nhf/touhou/houjuu_nue/__init__.py b/nhf/touhou/houjuu_nue/__init__.py
index 43d8b44..55f3614 100644
--- a/nhf/touhou/houjuu_nue/__init__.py
+++ b/nhf/touhou/houjuu_nue/__init__.py
@@ -24,7 +24,7 @@ from root to tip s0 (root),
 s1, s2, s3. The joints are named (from root to tip)
 shoulder, elbow, wrist in analogy with human anatomy.
 """
-from dataclasses import dataclass
+from dataclasses import dataclass, field
 import unittest
 import cadquery as Cq
 import nhf.joints
@@ -50,24 +50,24 @@ class Parameters:
     harness_height: float = 400
     harness_fillet: float = 10
 
-    harness_wing_base_pos = [
+    harness_wing_base_pos: list[tuple[str, float, float]] = field(default_factory=lambda: [
         ("r1", 70, 150),
         ("l1", -70, 150),
         ("r2", 100, 0),
         ("l2", -100, 0),
         ("r3", 70, -150),
         ("l3", -70, -150),
-    ]
+    ])
 
     # Holes drilled onto harness for attachment with HS joint
-    harness_to_root_conn_diam = 6
+    harness_to_root_conn_diam: float = 6
 
-    hs_hirth_joint: HirthJoint = HirthJoint(
+    hs_hirth_joint: HirthJoint = field(default_factory=lambda: HirthJoint(
         radius=30,
         radius_inner=20,
         tooth_height=10,
         base_height=5
-    )
+    ))
 
     # Wing root properties
     #
@@ -94,7 +94,7 @@ class Parameters:
     wing_r2_height: float = 100
     wing_r3_height: float = 100
 
-    trident_handle: Handle = Handle(
+    trident_handle: Handle = field(default_factory=lambda: Handle(
         diam=38,
         diam_inner=38-2 * 25.4/8,
         # M27-3
@@ -102,7 +102,7 @@ class Parameters:
         thread_pitch=3,
         diam_connector_internal=18,
         simplify_geometry=False,
-    )
+    ))
 
     def __post_init__(self):
         assert self.wing_root_radius > self.hs_hirth_joint.radius,\
diff --git a/nhf/touhou/houjuu_nue/test.py b/nhf/touhou/houjuu_nue/test.py
index cd0d17b..57d1aaa 100644
--- a/nhf/touhou/houjuu_nue/test.py
+++ b/nhf/touhou/houjuu_nue/test.py
@@ -12,7 +12,7 @@ class Test(unittest.TestCase):
         p = M.Parameters()
         obj = p.wing_root()
         #self.assertIsInstance(obj.solids(), Cq.Solid, msg="Wing root must be in one piece")
-        bbox = obj.BoundingBox()
+        bbox = obj.val().BoundingBox()
 
         msg = "Must fix 256^3 bbox"
         self.assertLess(bbox.xlen, 255, msg=msg)