diff --git a/nhf/handle.py b/nhf/handle.py
index 5bdd311..36462b8 100644
--- a/nhf/handle.py
+++ b/nhf/handle.py
@@ -36,7 +36,7 @@ class Handle:
     # Length for the rim on the female connector
     rim_length: float = 5
 
-    insertion_length: float = 60
+    insertion_length: float = 30
 
     # Amount by which the connector goes into the segment
     connector_length: float = 60
@@ -174,12 +174,15 @@ class Handle:
             )
         return result
 
-    def one_side_connector(self):
+    def one_side_connector(self, height=None):
+        if height is None:
+            height = self.rim_length
         result = (
             Cq.Workplane('XY')
             .cylinder(
                 radius=self.diam / 2,
-                height=self.rim_length,
+                height=height,
+                centered=(True, True, False)
             )
         )
         result.faces(">Z").tag("mate")
@@ -197,7 +200,7 @@ class Handle:
                 result
                 .union(
                     thread
-                    .located(Cq.Location((0, 0, self.connector_length / 2))))
+                    .located(Cq.Location((0, 0, height))))
             )
         return result
 
diff --git a/nhf/joints.py b/nhf/joints.py
index 29ff40b..1fb938b 100644
--- a/nhf/joints.py
+++ b/nhf/joints.py
@@ -223,7 +223,7 @@ def comma_assembly():
     )
     return result
 
-@dataclass(frozen=True)
+@dataclass
 class TorsionJoint:
     """
     This jonit consists of a rider puck on a track puck. IT is best suited if
@@ -260,6 +260,7 @@ class TorsionJoint:
         assert self.groove_radius_outer > self.groove_radius_inner
         assert self.groove_radius_inner > self.radius_spring
         assert self.spring_height > self.groove_depth, "Groove is too deep"
+        assert self.radius_spring > self.radius_axle
 
     @property
     def total_height(self):
diff --git a/nhf/touhou/houjuu_nue/trident.py b/nhf/touhou/houjuu_nue/trident.py
index 769213c..71901ab 100644
--- a/nhf/touhou/houjuu_nue/trident.py
+++ b/nhf/touhou/houjuu_nue/trident.py
@@ -5,9 +5,17 @@ from nhf.handle import Handle
 
 def trident_assembly(
         handle: Handle,
-        handle_segment_length: float = 24*25.4):
+        handle_segment_length: float = 24*25.4,
+        terminal_height=100):
     def segment():
         return handle.segment(handle_segment_length)
+
+    terminal = (
+        handle
+        .one_side_connector(height=terminal_height)
+        .faces(">Z")
+        .hole(15, terminal_height + handle.insertion_length - 10)
+    )
     mat_i = Material.PLASTIC_PLA
     mat_s = Material.ACRYLIC_BLACK
     assembly = (
@@ -28,5 +36,7 @@ def trident_assembly(
         .constrain("s2?mate2", "i3?rim", "Plane", param=0)
         .add(handle.one_side_connector(), name="head", color=mat_i.color)
         .constrain("i3?mate", "head?mate", "Plane")
+        .add(terminal, name="terminal", color=mat_i.color)
+        .constrain("i0?mate", "terminal?mate", "Plane")
     )
     return assembly.solve()