diff --git a/knob/knob.scad b/knob/knob.scad
new file mode 100644
index 0000000..8b53ffa
--- /dev/null
+++ b/knob/knob.scad
@@ -0,0 +1,18 @@
+$fn = 200;
+
+module shaft() {
+    difference() {
+        cylinder(h = 5, d = 6);
+        translate([2, -2.5, 0])
+            cube(5);
+    }
+
+    translate([0, 0, -5])
+        cylinder(h = 5, d = 7);
+}
+
+difference() {
+    cylinder(h = 16, d1 = 18, d2 = 15);
+    translate([0, 0, 5])
+        shaft();
+}