diff --git a/libtest.png b/libtest.png
index 8df74f8..e7dac46 100644
Binary files a/libtest.png and b/libtest.png differ
diff --git a/readme.md b/readme.md
index 456acc2..9e49a1e 100644
--- a/readme.md
+++ b/readme.md
@@ -2155,13 +2155,19 @@ Rocket switch. Also used for neon indicator in the same form factor.
 ---
 <a name="Rod"></a>
 ## Rod
-Steel rods, with optional chamfer.
+Steel rods and studding with chamfered ends.
 
 
 [vitamins/rod.scad](vitamins/rod.scad) Implementation.
 
 [tests/rod.scad](tests/rod.scad) Code for this example.
 
+### Modules
+| Module | Description |
+|:--- |:--- |
+| ```rod(d , l)``` | Draw a smooth rod with specified length and diameter |
+| ```studding(d , l)``` | Draw a threaded rod with specified length and diameter |
+
 ![rod](tests/png/rod.png)
 
 ### Vitamins
@@ -2174,6 +2180,13 @@ Steel rods, with optional chamfer.
 |   1 | ```rod(5, 80)``` |  Smooth rod 5mm x 80mm |
 |   1 | ```rod(6, 80)``` |  Smooth rod 6mm x 80mm |
 |   1 | ```rod(8, 80)``` |  Smooth rod 8mm x 80mm |
+|   1 | ```studding(10, 80)``` |  Threaded rod M10 x 80mm |
+|   1 | ```studding(12, 80)``` |  Threaded rod M12 x 80mm |
+|   1 | ```studding(3, 80)``` |  Threaded rod M3 x 80mm |
+|   1 | ```studding(4, 80)``` |  Threaded rod M4 x 80mm |
+|   1 | ```studding(5, 80)``` |  Threaded rod M5 x 80mm |
+|   1 | ```studding(6, 80)``` |  Threaded rod M6 x 80mm |
+|   1 | ```studding(8, 80)``` |  Threaded rod M8 x 80mm |
 
 
 <a href="#top">Top</a>
diff --git a/tests/png/rod.png b/tests/png/rod.png
index 2921e9e..8bfea67 100644
Binary files a/tests/png/rod.png and b/tests/png/rod.png differ
diff --git a/tests/rod.scad b/tests/rod.scad
index f83873a..0e25577 100644
--- a/tests/rod.scad
+++ b/tests/rod.scad
@@ -24,8 +24,13 @@ include <../vitamins/linear_bearings.scad>
 use <../vitamins/rod.scad>
 
 module rods()
-    layout([for(b = linear_bearings) 2 * bearing_radius(b)])
+    layout([for(b = linear_bearings) 2 * bearing_radius(b)]) {
+
         rod(bearing_rod_dia(linear_bearings[$i]), 80);
 
+        translate([0, 20])
+            studding(bearing_rod_dia(linear_bearings[$i]), 80);
+    }
+
 if($preview)
     rods();
diff --git a/vitamins/rod.scad b/vitamins/rod.scad
index eb4fba5..ffaed1f 100644
--- a/vitamins/rod.scad
+++ b/vitamins/rod.scad
@@ -18,13 +18,14 @@
 //
 
 //
-//! Steel rods, with optional chamfer.
+//! Steel rods and studding with chamfered ends.
 //
 include <../core.scad>
 
 rod_colour = grey80;
+studding_colour = grey70;
 
-module rod(d , l) {
+module rod(d , l) { //! Draw a smooth rod with specified length and diameter
     vitamin(str("rod(", d, ", ", l, "): Smooth rod ", d, "mm x ", l, "mm"));
 
     chamfer = d / 10;
@@ -35,3 +36,15 @@ module rod(d , l) {
             cylinder(d = d - 2 * chamfer, h = l, center = true);
         }
 }
+
+module studding(d , l) { //! Draw a threaded rod with specified length and diameter
+    vitamin(str("studding(", d, ", ", l,"): Threaded rod M", d, " x ", l, "mm"));
+
+    chamfer = d / 20;
+    color(studding_colour)
+        hull() {
+            cylinder(d = d, h = l - 2 * chamfer, center = true);
+
+            cylinder(d = d - 2 * chamfer, h = l, center = true);
+        }
+}