diff --git a/src/Mod/CAM/CAMTests/TestPathHelix.py b/src/Mod/CAM/CAMTests/TestPathHelix.py
index fc050e60a8..83026d23a8 100644
--- a/src/Mod/CAM/CAMTests/TestPathHelix.py
+++ b/src/Mod/CAM/CAMTests/TestPathHelix.py
@@ -72,7 +72,7 @@ class TestPathHelix(PathTestUtils.PathTestBase):
             model = base[0]
             for sub in base[1]:
                 pos = proxy.holePosition(model, sub)
-                self.assertRoughly(round(pos.Length / 10, 0), proxy.holeDiameter(op, model, sub))
+                self.assertRoughly(round(pos.Length / 10, 0), proxy.holeDiameter(model, sub))
 
     def test02(self):
         """Verify Helix generates proper holes for rotated model"""
@@ -88,9 +88,7 @@ class TestPathHelix(PathTestUtils.PathTestBase):
                 for sub in base[1]:
                     pos = proxy.holePosition(model, sub)
                     # Path.Log.track(deg, pos, pos.Length)
-                    self.assertRoughly(
-                        round(pos.Length / 10, 0), proxy.holeDiameter(op, model, sub)
-                    )
+                    self.assertRoughly(round(pos.Length / 10, 0), proxy.holeDiameter(model, sub))
 
     def test03(self):
         """Verify Helix generates proper holes for rotated base model"""
@@ -112,9 +110,7 @@ class TestPathHelix(PathTestUtils.PathTestBase):
                 for sub in base[1]:
                     pos = proxy.holePosition(model, sub)
                     # Path.Log.track(deg, pos, pos.Length)
-                    self.assertRoughly(
-                        round(pos.Length / 10, 0), proxy.holeDiameter(op, model, sub)
-                    )
+                    self.assertRoughly(round(pos.Length / 10, 0), proxy.holeDiameter(model, sub))
 
     def test04(self):
         """Verify Helix generates proper holes for rotated clone base model"""
@@ -136,9 +132,7 @@ class TestPathHelix(PathTestUtils.PathTestBase):
                 for sub in base[1]:
                     pos = proxy.holePosition(model, sub)
                     # Path.Log.track(deg, pos, pos.Length)
-                    self.assertRoughly(
-                        round(pos.Length / 10, 0), proxy.holeDiameter(op, model, sub)
-                    )
+                    self.assertRoughly(round(pos.Length / 10, 0), proxy.holeDiameter(model, sub))
 
     def testPathDirection(self):
         """Verify that the generated paths obeys the given parameters"""
diff --git a/src/Mod/CAM/Path/Op/CircularHoleBase.py b/src/Mod/CAM/Path/Op/CircularHoleBase.py
index c1723f366a..3001ae452e 100644
--- a/src/Mod/CAM/Path/Op/CircularHoleBase.py
+++ b/src/Mod/CAM/Path/Op/CircularHoleBase.py
@@ -88,24 +88,20 @@ class ObjectOp(PathOp.ObjectOp):
         Can safely be overwritten by subclasses."""
         pass
 
-    def holeDiameter(self, obj, base, sub):
-        """holeDiameter(obj, base, sub) ... returns the diameter of the specified hole."""
+    def holeDiameter(self, base, sub):
+        """holeDiameter(base, sub) ... returns the diameter of the specified hole."""
         try:
             shape = base.Shape.getElement(sub)
-            if shape.ShapeType == "Vertex":
+            if isinstance(shape, Part.Vertex):
                 return 0
 
-            if shape.ShapeType == "Edge" and type(shape.Curve) == Part.Circle:
+            if isinstance(shape, Part.Edge) and isinstance(shape.Curve, Part.Circle):
                 return shape.Curve.Radius * 2
 
-            if shape.ShapeType == "Face":
-                for i in range(len(shape.Edges)):
-                    if (
-                        type(shape.Edges[i].Curve) == Part.Circle
-                        and shape.Edges[i].Curve.Radius * 2 < shape.BoundBox.XLength * 1.1
-                        and shape.Edges[i].Curve.Radius * 2 > shape.BoundBox.XLength * 0.9
-                    ):
-                        return shape.Edges[i].Curve.Radius * 2
+            if isinstance(shape, Part.Face):
+                for edge in shape.Edges:
+                    if isinstance(edge.Curve, Part.Circle):
+                        return edge.Curve.Radius * 2
 
             # for all other shapes the diameter is just the dimension in X.
             # This may be inaccurate as the BoundBox is calculated on the tessellated geometry
@@ -183,7 +179,7 @@ class ObjectOp(PathOp.ObjectOp):
                             {
                                 "x": pos.x,
                                 "y": pos.y,
-                                "r": self.holeDiameter(obj, base, sub),
+                                "r": self.holeDiameter(base, sub),
                             }
                         )
 
diff --git a/src/Mod/CAM/Path/Op/Gui/CircularHoleBase.py b/src/Mod/CAM/Path/Op/Gui/CircularHoleBase.py
index 37b6d5b6b1..66cf6b2145 100644
--- a/src/Mod/CAM/Path/Op/Gui/CircularHoleBase.py
+++ b/src/Mod/CAM/Path/Op/Gui/CircularHoleBase.py
@@ -84,7 +84,7 @@ class TaskPanelHoleGeometryPage(PathOpGui.TaskPanelBaseGeometryPage):
                 item.setData(self.DataObjectSub, sub)
                 self.form.baseList.setItem(self.form.baseList.rowCount() - 1, 0, item)
 
-                dia = obj.Proxy.holeDiameter(obj, base, sub)
+                dia = obj.Proxy.holeDiameter(base, sub)
                 item = QtGui.QTableWidgetItem()
                 item.setData(QtCore.Qt.DisplayRole, float(dia))
                 item.setTextAlignment(QtCore.Qt.AlignHCenter)