diff --git a/nhf/handle.py b/nhf/handle.py
index 0424569..5bdd311 100644
--- a/nhf/handle.py
+++ b/nhf/handle.py
@@ -74,11 +74,13 @@ class Handle:
         result.faces(">Z").tag("mate2")
         return result
 
-    def _external_thread(self):
+    def _external_thread(self, length=None):
+        if length is None:
+            length = self.insertion_length
         return NMt.external_metric_thread(
             self.diam_threading,
             self.thread_pitch,
-            self.insertion_length,
+            length,
             top_lead_in=True)
     def _internal_thread(self):
         return NMt.internal_metric_thread(
@@ -86,7 +88,7 @@ class Handle:
             self.thread_pitch,
             self.insertion_length)
 
-    def insertion(self):
+    def insertion(self, holes=[]):
         """
         This type of joint is used to connect two handlebar pieces. Each handlebar
         piece is a tube which cannot be machined, so the joint connects to the
@@ -95,6 +97,12 @@ class Handle:
         Tags:
         * lip: Co-planar Mates to the rod
         * mate: Mates to the connector
+
+        WARNING: A tolerance lower than the defualt (maybe 5e-4) is required for
+        STL export.
+
+        Set `holes` to the heights for drilling holes into the model for resin
+        to flow out.
         """
         result = (
             Cq.Workplane('XY')
@@ -117,12 +125,22 @@ class Handle:
         if not self.simplify_geometry:
             thread = self._internal_thread().val()
             result = result.union(thread)
+        for h in holes:
+            cyl = Cq.Solid.makeCylinder(
+                radius=2,
+                height=self.diam * 2,
+                pnt=(-self.diam, 0, h),
+                dir=(1, 0, 0))
+            result = result.cut(cyl)
         return result
 
-    def connector(self, solid: bool = False):
+    def connector(self, solid: bool = True):
         """
         Tags:
         * mate{1,2}: Mates to the connector
+
+        WARNING: A tolerance lower than the defualt (maybe 2e-4) is required for
+        STL export.
         """
         result = (
             Cq.Workplane('XY')
@@ -151,7 +169,7 @@ class Handle:
                     .located(Cq.Location((0, 0, self.connector_length / 2))))
                 .union(
                     thread
-                    .rotate((0,0,0), (1,0,0), angleDegrees=90)
+                    .rotate((0,0,0), (1,0,0), angleDegrees=180)
                     .located(Cq.Location((0, 0, -self.connector_length / 2))))
             )
         return result
@@ -183,6 +201,28 @@ class Handle:
             )
         return result
 
+    def threaded_core(self, length):
+        """
+        Generates a threaded core for unioning with other components
+        """
+        result = (
+            Cq.Workplane('XY')
+            .cylinder(
+                radius=self.diam_connector_external / 2,
+                height=length,
+                centered=(True, True, False),
+            )
+        )
+        result.faces(">Z").tag("mate")
+        result.faces("<Z").tag("base")
+        if not self.simplify_geometry:
+            thread = self._external_thread(length=length).val()
+            result = (
+                result
+                .union(thread)
+            )
+        return result
+
     def connector_insertion_assembly(self):
         connector_color = Cq.Color(0.8,0.8,0.5,0.3)
         insertion_color = Cq.Color(0.7,0.7,0.7,0.3)
diff --git a/nhf/touhou/houjuu_nue/__init__.py b/nhf/touhou/houjuu_nue/__init__.py
index f059eca..43d8b44 100644
--- a/nhf/touhou/houjuu_nue/__init__.py
+++ b/nhf/touhou/houjuu_nue/__init__.py
@@ -96,7 +96,7 @@ class Parameters:
 
     trident_handle: Handle = Handle(
         diam=38,
-        diam_inner=33,
+        diam_inner=38-2 * 25.4/8,
         # M27-3
         diam_threading=27,
         thread_pitch=3,