diff --git a/src/__private__/__shape_arc.scad b/src/__private__/__shape_arc.scad
new file mode 100644
index 00000000..404e1ac7
--- /dev/null
+++ b/src/__private__/__shape_arc.scad
@@ -0,0 +1,40 @@
+function __edge_r_begin(orig_r, a, a_step, m) =
+    let(leng = orig_r * cos(a_step / 2))
+    leng / cos((m - 0.5) * a_step - a);
+
+function __edge_r_end(orig_r, a, a_step, n) =      
+    let(leng = orig_r * cos(a_step / 2))    
+    leng / cos((n + 0.5) * a_step - a);
+
+function __shape_arc(radius, angle, width, width_mode = "LINE_CROSS") =
+    let(
+        w_offset = width_mode == "LINE_CROSS" ? [width / 2, -width / 2] : (
+            width_mode == "LINE_INWARD" ? [0, -width] : [width, 0]
+        ),
+        frags = __frags(radius),
+        a_step = 360 / frags,
+        half_a_step = a_step / 2,
+        angles = __is_vector(angle) ? angle : [0, angle],
+        m = floor(angles[0] / a_step) + 1,
+        n = floor(angles[1] / a_step),
+        r_outer = radius + w_offset[0],
+        r_inner = radius + w_offset[1],
+        points = concat(
+            // outer arc path
+            [__ra_to_xy(__edge_r_begin(r_outer, angles[0], a_step, m), angles[0])],
+            m > n ? [] : [
+                for(i = [m:n]) 
+                    __ra_to_xy(r_outer, a_step * i)
+            ],
+            angles[1] == a_step * n ? [] : [__ra_to_xy(__edge_r_end(r_outer, angles[1], a_step, n), angles[1])],
+            // inner arc path
+            angles[1] == a_step * n ? [] : [__ra_to_xy(__edge_r_end(r_inner, angles[1], a_step, n), angles[1])],
+            m > n ? [] : [
+                for(i = [m:n]) 
+                    let(idx = (n + (m - i)))
+                    __ra_to_xy(r_inner, a_step * idx)
+
+            ],
+            [__ra_to_xy(__edge_r_begin(r_inner, angles[0], a_step, m), angles[0])]        
+        )
+    ) points;
\ No newline at end of file
diff --git a/src/shape_arc.scad b/src/shape_arc.scad
index 93b4b41d..ca8c1463 100644
--- a/src/shape_arc.scad
+++ b/src/shape_arc.scad
@@ -15,44 +15,7 @@
 include <__private__/__frags.scad>;
 include <__private__/__is_vector.scad>;
 include <__private__/__ra_to_xy.scad>;
-    
-function __edge_r_begin(orig_r, a, a_step, m) =
-    let(leng = orig_r * cos(a_step / 2))
-    leng / cos((m - 0.5) * a_step - a);
-
-function __edge_r_end(orig_r, a, a_step, n) =      
-    let(leng = orig_r * cos(a_step / 2))    
-    leng / cos((n + 0.5) * a_step - a);
+include <__private__/__shape_arc.scad>;
 
 function shape_arc(radius, angle, width, width_mode = "LINE_CROSS") =
-    let(
-        w_offset = width_mode == "LINE_CROSS" ? [width / 2, -width / 2] : (
-            width_mode == "LINE_INWARD" ? [0, -width] : [width, 0]
-        ),
-        frags = __frags(radius),
-        a_step = 360 / frags,
-        half_a_step = a_step / 2,
-        angles = __is_vector(angle) ? angle : [0, angle],
-        m = floor(angles[0] / a_step) + 1,
-        n = floor(angles[1] / a_step),
-        r_outer = radius + w_offset[0],
-        r_inner = radius + w_offset[1],
-        points = concat(
-            // outer arc path
-            [__ra_to_xy(__edge_r_begin(r_outer, angles[0], a_step, m), angles[0])],
-            m > n ? [] : [
-                for(i = [m:n]) 
-                    __ra_to_xy(r_outer, a_step * i)
-            ],
-            angles[1] == a_step * n ? [] : [__ra_to_xy(__edge_r_end(r_outer, angles[1], a_step, n), angles[1])],
-            // inner arc path
-            angles[1] == a_step * n ? [] : [__ra_to_xy(__edge_r_end(r_inner, angles[1], a_step, n), angles[1])],
-            m > n ? [] : [
-                for(i = [m:n]) 
-                    let(idx = (n + (m - i)))
-                    __ra_to_xy(r_inner, a_step * idx)
-
-            ],
-            [__ra_to_xy(__edge_r_begin(r_inner, angles[0], a_step, m), angles[0])]        
-        )
-    ) points;
\ No newline at end of file
+    __shape_arc(radius, angle, width, width_mode);
\ No newline at end of file