diff --git a/tests/shaft_couplings.scad b/tests/shaft_couplings.scad
new file mode 100644
index 0000000..f1613fd
--- /dev/null
+++ b/tests/shaft_couplings.scad
@@ -0,0 +1,30 @@
+//
+// NopSCADlib Copyright Chris Palmer 2018
+// nop.head@gmail.com
+// hydraraptor.blogspot.com
+//
+// This file is part of NopSCADlib.
+//
+// NopSCADlib is free software: you can redistribute it and/or modify it under the terms of the
+// GNU General Public License as published by the Free Software Foundation, either version 3 of
+// the License, or (at your option) any later version.
+//
+// NopSCADlib is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+// without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+// See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with NopSCADlib.
+// If not, see <https://www.gnu.org/licenses/>.
+//
+include <../core.scad>
+include <../vitamins/shaft_couplings.scad>
+
+use <../utils/layout.scad>
+
+module shaft_couplings()
+    layout([for(s = shaft_couplings) sc_diameter(s)],5)
+        shaft_coupling(shaft_couplings[$i]);
+
+if($preview)
+    shaft_couplings();
+
diff --git a/vitamins/shaft_coupling.scad b/vitamins/shaft_coupling.scad
new file mode 100644
index 0000000..a42b062
--- /dev/null
+++ b/vitamins/shaft_coupling.scad
@@ -0,0 +1,61 @@
+//
+// NopSCADlib Copyright Chris Palmer 2020
+// nop.head@gmail.com
+// hydraraptor.blogspot.com
+//
+// This file is part of NopSCADlib.
+//
+// NopSCADlib is free software: you can redistribute it and/or modify it under the terms of the
+// GNU General Public License as published by the Free Software Foundation, either version 3 of
+// the License, or (at your option) any later version.
+//
+// NopSCADlib is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+// without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+// See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with NopSCADlib.
+// If not, see <https://www.gnu.org/licenses/>.
+
+//
+//! Shaft couplings
+//
+include <../core.scad>
+
+
+function sc_length(type)       = type[1]; //! Coupling length
+function sc_diameter(type)     = type[2]; //! Coupling outer diameter
+function sc_diameter1(type)    = type[3]; //! Diameter of smaller shaft
+function sc_diameter2(type)    = type[4]; //! Diameter of larger shaft
+
+module shaft_coupling(type, colour = "silver") { //! Draw the shaft coupling
+    vitamin(str("shaft_coupling(", type[0], "): Shaft coupling ", type[0]));
+
+    length = sc_length(type);
+    diameter = sc_diameter(type);
+    d1 = sc_diameter1(type);
+    d2 = sc_diameter2(type);
+
+    color(colour) {
+        translate_z(-length / 2)
+            linear_extrude(length / 2)
+                difference() {
+                    circle(d = diameter);
+                    circle(d = d1);
+                }
+        linear_extrude(length / 2)
+            difference() {
+                circle(d = diameter);
+                circle(d = d2);
+            }
+    }
+
+    grub_offset_z = 5;
+    grub_length = 3;
+    for(z = [-length / 2 + grub_offset_z, length / 2 - grub_offset_z])
+        translate_z(z)
+            for(a = [0, 90])
+                rotate([-90, 0, a])
+                    translate_z(diameter / 2 + 1)
+                        not_on_bom() screw(M3_grub_screw, grub_length);
+}
+
diff --git a/vitamins/shaft_couplings.scad b/vitamins/shaft_couplings.scad
new file mode 100644
index 0000000..c105dd0
--- /dev/null
+++ b/vitamins/shaft_couplings.scad
@@ -0,0 +1,30 @@
+//
+// NopSCADlib Copyright Chris Palmer 2020
+// nop.head@gmail.com
+// hydraraptor.blogspot.com
+//
+// This file is part of NopSCADlib.
+//
+// NopSCADlib is free software: you can redistribute it and/or modify it under the terms of the
+// GNU General Public License as published by the Free Software Foundation, either version 3 of
+// the License, or (at your option) any later version.
+//
+// NopSCADlib is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+// without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+// See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with NopSCADlib.
+// If not, see <https://www.gnu.org/licenses/>.
+//
+
+//
+//! Shaft couplings
+//
+
+//                                 L     D    d1   d2
+SC_5x8_rigid  = [ "5x8 rigid",    25, 12.5,    5,   8 ];
+
+shaft_couplings = [SC_5x8_rigid];
+
+use <shaft_coupling.scad>
+