diff --git a/nhf/touhou/yasaka_kanako/onbashira.py b/nhf/touhou/yasaka_kanako/onbashira.py
index bd8cd0a..08d2177 100644
--- a/nhf/touhou/yasaka_kanako/onbashira.py
+++ b/nhf/touhou/yasaka_kanako/onbashira.py
@@ -129,6 +129,7 @@ class FlangeCoupler(Model):
             loc = Cq.Location.rot2d(i * 360 / self.n_hole_flange) * Cq.Location(self.r_hole_flange, 0)
             result.tagAbsolute(f"holeT{i}", loc * Cq.Location(0, 0, self.height_flange), direction="+Z")
             result.tagAbsolute(f"holeB{i}", loc, direction="-Z")
+        result.tagAbsolute("dir", (0, 0, self.height_hole), direction="+X")
         return result
 
 
@@ -215,6 +216,7 @@ class Motor(Model):
         result.tagAbsolute("anchor1", (self.dx_anchor, 0, z_anchor), direction="+Z")
         result.tagAbsolute("anchor2", (-self.dx_anchor, 0, z_anchor), direction="+Z")
         result.tagAbsolute("shaft", (0, 0, self.height_body + self.height_base_shaft), direction="+Z")
+        result.tagAbsolute("dir", (0, 0, self.height_body + self.height_hole), direction="+X")
         return result
 
 
@@ -611,7 +613,13 @@ class Onbashira(Model):
             .constrain(
                 "flange_coupler?top",
                 "motor?shaft",
-                "Plane"
+                "Axis"
+            )
+            .constrain(
+                "flange_coupler?dir",
+                "motor?dir",
+                "Plane",
+                param=0,
             )
         )
         for i in range(self.flange_coupler.n_hole_flange):