diff --git a/libtest.png b/libtest.png
index 9a3e942..c779512 100644
Binary files a/libtest.png and b/libtest.png differ
diff --git a/libtest.scad b/libtest.scad
index 5efe5f5..6a5169d 100644
--- a/libtest.scad
+++ b/libtest.scad
@@ -226,7 +226,7 @@ translate([950, 1525])
 
 inserts_y = 0;
 nuts_y = inserts_y + 20;
-washers_y = nuts_y + 120;
+washers_y = nuts_y + 140;
 screws_y = washers_y + 120;
 circlips_y = screws_y + 180;
 springs_y = circlips_y + 20;
diff --git a/readme.md b/readme.md
index 61c47d7..35d4695 100644
--- a/readme.md
+++ b/readme.md
@@ -2348,6 +2348,7 @@ If a nut is given a child then it gets placed on its top surface.
 ### Properties
 | Function | Description |
 |:--- |:--- |
+| `nut_dome(type)` | Dome height and max thread depth if a domed acorn nut |
 | `nut_pitch(type)` | Pitch if not standard metric course thread |
 | `nut_radius(type)` | Radius across the corners |
 | `nut_size(type)` | Diameter of the corresponding screw |
@@ -2360,8 +2361,10 @@ If a nut is given a child then it gets placed on its top surface.
 ### Functions
 | Function | Description |
 |:--- |:--- |
+| `nut_dome_height(type)` | Height of the domed version |
 | `nut_flat_radius(type)` | Radius across the flats |
 | `nut_thickness(type, nyloc = false)` | Thickness of plain or nyloc version |
+| `nut_thread_depth(type)` | Max thread depth in domed version |
 | `nut_trap_flat_radius(nut, horizontal = false)` | Radius across the flats of a nut trap |
 | `nut_trap_radius(nut, horizontal = false)` | Radius across the corners of a nut trap |
 | `t_nut_tab(type)` | Sliding t-nut T dimensions |
@@ -2369,7 +2372,7 @@ If a nut is given a child then it gets placed on its top surface.
 ### Modules
 | Module | Description |
 |:--- |:--- |
-| `nut(type, nyloc = false, brass = false, nylon = false)` | Draw specified nut |
+| `nut(type, nyloc = false, brass = false, nylon = false, dome = false)` | Draw specified nut |
 | `nut_and_washer(type, nyloc)` | Draw nut with corresponding washer |
 | `nut_square(type, brass = false, nylon = false)` | Draw specified square nut |
 | `nut_trap(screw, nut, depth = 0, horizontal = false, supported = false, h = 200)` | Make a nut trap |
@@ -2390,24 +2393,29 @@ If a nut is given a child then it gets placed on its top surface.
 |   1 | `sliding_t_nut(M3_sliding_t_nut)` |  Nut M3 sliding T |
 |   1 | `nut(M3_nut)` |  Nut M3 x 2.4mm  |
 |   1 | `nut(M3_nut, brass = true)` |  Nut M3 x 2.4mm brass |
+|   1 | `nut(M3_nut, dome = true)` |  Nut M3 x 2.4mm domed |
 |   1 | `nut(M3_nut, nyloc = true)` |  Nut M3 x 2.4mm nyloc |
 |   1 | `nut(M3nS_thin_nut)` |  Nut M3nS 5.5 x 1.8mm  |
 |   1 | `sliding_t_nut(M4_hammer_nut)` |  Nut M4 hammer |
 |   1 | `sliding_t_nut(M4_sliding_t_nut)` |  Nut M4 sliding T |
 |   1 | `nut(M4_nut)` |  Nut M4 x 3.2mm  |
+|   1 | `nut(M4_nut, dome = true)` |  Nut M4 x 3.2mm domed |
 |   1 | `nut(M4_nut, nyloc = true)` |  Nut M4 x 3.2mm nyloc |
 |   1 | `nut(M4nS_thin_nut)` |  Nut M4nS 7 x 2.2mm  |
 |   1 | `sliding_t_nut(M5_sliding_t_nut)` |  Nut M5 sliding T |
 |   1 | `nut(M5_nut)` |  Nut M5 x 4mm  |
+|   1 | `nut(M5_nut, dome = true)` |  Nut M5 x 4mm domed |
 |   1 | `nut(M5_nut, nyloc = true)` |  Nut M5 x 4mm nyloc |
 |   1 | `nut(M5nS_thin_nut)` |  Nut M5nS 8 x 2.7mm  |
 |   1 | `sliding_t_nut(M6_sliding_t_nut)` |  Nut M6 hammer |
 |   1 | `nut(M6_half_nut)` |  Nut M6 x 3mm  |
 |   1 | `nut(M6_nut)` |  Nut M6 x 5mm  |
+|   1 | `nut(M6_nut, dome = true)` |  Nut M6 x 5mm domed |
 |   1 | `nut(M6_nut, nyloc = true)` |  Nut M6 x 5mm nyloc |
 |   1 | `nut(M6nS_thin_nut)` |  Nut M6nS 10 x 3.2mm  |
 |   1 | `sliding_t_nut(M8_sliding_ball_t_nut)` |  Nut M8 sliding T with spring loaded ball |
 |   1 | `nut(M8_nut)` |  Nut M8 x 6.5mm  |
+|   1 | `nut(M8_nut, dome = true)` |  Nut M8 x 6.5mm domed |
 |   1 | `nut(M8_nut, nyloc = true)` |  Nut M8 x 6.5mm nyloc |
 |   1 | `nut(M8nS_thin_nut)` |  Nut M8nS 13 x 4mm  |
 |   1 | `washer(M6_washer)` |  Washer  M6 x 12.5mm x 1.5mm |
diff --git a/tests/fuseholder.scad b/tests/fuseholder.scad
index aab8cf5..c9e1d66 100644
--- a/tests/fuseholder.scad
+++ b/tests/fuseholder.scad
@@ -20,8 +20,10 @@ include <../utils/core/core.scad>
 
 use <../vitamins/fuseholder.scad>
 
+thickness = 6;
+
 module fuseholders()
-    fuseholder(6);
+    fuseholder(thickness);
 
 if($preview)
     let($show_threads = 1)
diff --git a/tests/nuts.scad b/tests/nuts.scad
index 4a3e499..9659629 100644
--- a/tests/nuts.scad
+++ b/tests/nuts.scad
@@ -25,7 +25,11 @@ module nuts() {
             translate([0, nyloc ? 20 : 0])
                 nut(n, nyloc);
 
-        translate([0, 40]) {
+        translate([0, 40])
+            if(nut_dome(n))
+                nut(n, dome = true);
+
+        translate([0, 60]) {
             if(n == M3_nut)
                 nut(n, brass = true);
 
@@ -43,7 +47,7 @@ module nuts() {
                 #nut_trap(M8_cap_screw, n, h = 30);
         }
 
-        translate([0, 60]) {
+        translate([0, 80]) {
             if(n == M3_nut)
                 sliding_t_nut(M3_sliding_t_nut);
 
@@ -61,7 +65,7 @@ module nuts() {
                     sliding_t_nut(M8_sliding_ball_t_nut);
         }
 
-        translate([0, 80]) {
+        translate([0, 100]) {
             if(n == M3_nut)
                 sliding_t_nut(M3_hammer_nut);
 
@@ -69,7 +73,7 @@ module nuts() {
                 sliding_t_nut(M4_hammer_nut);
        }
 
-       translate([0, 100]) {
+       translate([0, 120]) {
             if(n == M3_nut)
                nut_square(M3nS_thin_nut);
             if(n == M4_nut)
diff --git a/tests/png/antennas.png b/tests/png/antennas.png
index a308546..3a6a6a2 100644
Binary files a/tests/png/antennas.png and b/tests/png/antennas.png differ
diff --git a/tests/png/axials.png b/tests/png/axials.png
index 4cd691b..dcfbbfb 100644
Binary files a/tests/png/axials.png and b/tests/png/axials.png differ
diff --git a/tests/png/bearing_blocks.png b/tests/png/bearing_blocks.png
index 6794b42..84ae37b 100644
Binary files a/tests/png/bearing_blocks.png and b/tests/png/bearing_blocks.png differ
diff --git a/tests/png/cable_clip.png b/tests/png/cable_clip.png
index 822eb02..559cd3d 100644
Binary files a/tests/png/cable_clip.png and b/tests/png/cable_clip.png differ
diff --git a/tests/png/camera_housing.png b/tests/png/camera_housing.png
index 1ff0a5c..b6ef415 100644
Binary files a/tests/png/camera_housing.png and b/tests/png/camera_housing.png differ
diff --git a/tests/png/door_hinge.png b/tests/png/door_hinge.png
index c2be601..41e6845 100644
Binary files a/tests/png/door_hinge.png and b/tests/png/door_hinge.png differ
diff --git a/tests/png/door_latch.png b/tests/png/door_latch.png
index f566c86..3b6a297 100644
Binary files a/tests/png/door_latch.png and b/tests/png/door_latch.png differ
diff --git a/tests/png/fans.png b/tests/png/fans.png
index b1a7d17..ad1ceea 100644
Binary files a/tests/png/fans.png and b/tests/png/fans.png differ
diff --git a/tests/png/flat_hinge.png b/tests/png/flat_hinge.png
index 6a6e5b7..bd9a01e 100644
Binary files a/tests/png/flat_hinge.png and b/tests/png/flat_hinge.png differ
diff --git a/tests/png/foot.png b/tests/png/foot.png
index a762742..8146aea 100644
Binary files a/tests/png/foot.png and b/tests/png/foot.png differ
diff --git a/tests/png/fuseholder.png b/tests/png/fuseholder.png
index b71976d..68fe7e0 100644
Binary files a/tests/png/fuseholder.png and b/tests/png/fuseholder.png differ
diff --git a/tests/png/iecs.png b/tests/png/iecs.png
index 4619b1a..fb0f9ec 100644
Binary files a/tests/png/iecs.png and b/tests/png/iecs.png differ
diff --git a/tests/png/jack.png b/tests/png/jack.png
index e655bd5..38027b8 100644
Binary files a/tests/png/jack.png and b/tests/png/jack.png differ
diff --git a/tests/png/modules.png b/tests/png/modules.png
index 7a01193..e0e47e0 100644
Binary files a/tests/png/modules.png and b/tests/png/modules.png differ
diff --git a/tests/png/nuts.png b/tests/png/nuts.png
index 6739055..85d6ac6 100644
Binary files a/tests/png/nuts.png and b/tests/png/nuts.png differ
diff --git a/tests/png/pcb_mount.png b/tests/png/pcb_mount.png
index 5fc34aa..3d32bab 100644
Binary files a/tests/png/pcb_mount.png and b/tests/png/pcb_mount.png differ
diff --git a/tests/png/pcbs.png b/tests/png/pcbs.png
index 382b121..76563fd 100644
Binary files a/tests/png/pcbs.png and b/tests/png/pcbs.png differ
diff --git a/tests/png/pillow_blocks.png b/tests/png/pillow_blocks.png
index 8639921..9583d1f 100644
Binary files a/tests/png/pillow_blocks.png and b/tests/png/pillow_blocks.png differ
diff --git a/tests/png/pocket_handle.png b/tests/png/pocket_handle.png
index bd73e03..ef809de 100644
Binary files a/tests/png/pocket_handle.png and b/tests/png/pocket_handle.png differ
diff --git a/tests/png/polyholes.png b/tests/png/polyholes.png
index 6404177..e0b6d4c 100644
Binary files a/tests/png/polyholes.png and b/tests/png/polyholes.png differ
diff --git a/tests/png/potentiometers.png b/tests/png/potentiometers.png
index fe4bbd4..0c29215 100644
Binary files a/tests/png/potentiometers.png and b/tests/png/potentiometers.png differ
diff --git a/tests/png/rails.png b/tests/png/rails.png
index 6cc789c..46b1bc2 100644
Binary files a/tests/png/rails.png and b/tests/png/rails.png differ
diff --git a/tests/png/ring_terminals.png b/tests/png/ring_terminals.png
index 4b2e09a..f680c47 100644
Binary files a/tests/png/ring_terminals.png and b/tests/png/ring_terminals.png differ
diff --git a/tests/png/round.png b/tests/png/round.png
index 57ec684..0bb3977 100644
Binary files a/tests/png/round.png and b/tests/png/round.png differ
diff --git a/tests/png/screw_knob.png b/tests/png/screw_knob.png
index 3c11601..ec4107f 100644
Binary files a/tests/png/screw_knob.png and b/tests/png/screw_knob.png differ
diff --git a/tests/png/screws.png b/tests/png/screws.png
index 934fb2e..64afde1 100644
Binary files a/tests/png/screws.png and b/tests/png/screws.png differ
diff --git a/tests/png/sk_brackets.png b/tests/png/sk_brackets.png
index 3b684df..f9d5ed2 100644
Binary files a/tests/png/sk_brackets.png and b/tests/png/sk_brackets.png differ
diff --git a/tests/png/socket_box.png b/tests/png/socket_box.png
index 99e017e..a05b089 100644
Binary files a/tests/png/socket_box.png and b/tests/png/socket_box.png differ
diff --git a/tests/png/ssrs.png b/tests/png/ssrs.png
index 1b644d3..1b14b27 100644
Binary files a/tests/png/ssrs.png and b/tests/png/ssrs.png differ
diff --git a/tests/png/toggles.png b/tests/png/toggles.png
index 53d4e0f..e6408e1 100644
Binary files a/tests/png/toggles.png and b/tests/png/toggles.png differ
diff --git a/tests/png/veroboard.png b/tests/png/veroboard.png
index 9bbda4e..c6822db 100644
Binary files a/tests/png/veroboard.png and b/tests/png/veroboard.png differ
diff --git a/vitamins/fuseholder.scad b/vitamins/fuseholder.scad
index 6ec65c0..95010c8 100644
--- a/vitamins/fuseholder.scad
+++ b/vitamins/fuseholder.scad
@@ -20,7 +20,7 @@
 //
 //! 20mm panel mount fuse holder.
 //
-include <../utils/core/core.scad>
+include <../core.scad>
 include <spades.scad>
 use <../utils/tube.scad>
 use <../utils/thread.scad>
@@ -69,18 +69,10 @@ module fuseholder(thickness) { //! Fuseholder with nut in place for specified pa
     vflip()
         translate_z(thickness)
             explode(height, explode_children = true) {
-                color(colour) {
+                color(colour)
                     tube(or = nut_d / 2, ir = thread_d / 2, h = nut_flange_t, center = false);
 
-                    linear_extrude(nut_t)
-                        difference() {
-                            circle(d = nut_d, $fn = 6);
-
-                            circle(d = thread_d);
-                        }
-                }
-                if(show_threads && exploded())
-                    female_metric_thread(thread_d, thread_p, nut_t, false, colour = colour);
+                draw_nut(nut_d, thread_d, nut_t, thread_p, colour, show_threads && exploded() || thickness > thread);
             }
     //
     // Body
diff --git a/vitamins/jack.scad b/vitamins/jack.scad
index d34c8cd..40d0224 100644
--- a/vitamins/jack.scad
+++ b/vitamins/jack.scad
@@ -149,18 +149,8 @@ module jack_4mm_plastic(colour, thickness, display_colour = false) { //! Draw a
     }
     translate_z(-thickness)
         explode(-length)
-            vflip() {
-                color(silver)
-                    linear_extrude(nut_t)
-                        difference() {
-                            circle(d = nut_d, $fn = 6);
-
-                            circle(d = thread_d);
-                        }
-
-                if(show_threads)
-                    female_metric_thread(thread_d, thread_p, nut_t, false, colour = silver);
-            }
+            vflip()
+                draw_nut(nut_d, thread_d, nut_t, thread_p, silver, show_threads);
 }
 
 function jack_4mm_shielded_hole_radius() = 12 / 2; //! Panel hole radius for 4mm shielded jack
@@ -282,14 +272,7 @@ module post_4mm(colour, thickness, display_colour = false) { //! Draw a 4mm bind
     module nut() {
         nut_t = 2.3;
 
-        color(silver)
-            linear_extrude(nut_t) difference() {
-                circle(d = 6.3 / cos(30), $fn = 6);
-
-                circle(d = thread_d);
-            }
-        if(show_threads)
-            female_metric_thread(thread_d, thread_p, nut_t, false, colour = silver);
+        draw_nut(6.3 / cos(30), thread_d, nut_t, thread_p, silver, show_threads);
 
         translate_z(nut_t)
             children();
@@ -498,16 +481,6 @@ module power_jack(thickness) { //! Draw a power jack socket with nut positioned
     // Nut
     translate_z(-thickness)
         explode(-length)
-            vflip() {
-                color(silver)
-                    linear_extrude(nut_t)
-                        difference() {
-                            circle(d = nut_d, $fn = 6);
-
-                            circle(d = thread_d);
-                        }
-
-                if(show_threads)
-                    female_metric_thread(thread_d, thread_p, nut_t, false, colour = silver);
-            }
+            vflip()
+                draw_nut(nut_d, thread_d, nut_t, thread_p, silver, show_threads);
 }
diff --git a/vitamins/nut.scad b/vitamins/nut.scad
index 2e554b0..f803a3d 100644
--- a/vitamins/nut.scad
+++ b/vitamins/nut.scad
@@ -37,6 +37,7 @@ function nut_thickness(type, nyloc = false) = nyloc ? type[4] : type[3]; //! Thi
 function nut_washer(type)     = type[5];        //! Corresponding washer
 function nut_trap_depth(type) = type[6];        //! Depth of nut trap
 function nut_pitch(type)      = type[7];        //! Pitch if not standard metric course thread
+function nut_dome(type)       = type[8];        //! Dome height and max thread depth if a domed acorn nut
 
 function nut_flat_radius(type) = nut_radius(type) * cos(30); //! Radius across the flats
 
@@ -44,36 +45,84 @@ function nut_square_size(type)      = type[1]; //! Diameter of the corresponding
 function nut_square_width(type)     = type[2]; //! Width of the square nut
 function nut_square_thickness(type) = type[3]; //! Thickness of the square nut
 
-module nut(type, nyloc = false, brass = false, nylon = false) { //! Draw specified nut
+function nut_dome_height(type)  = let(d = nut_dome(type)) d ? d[0] : nut_thickness(type); //! Height of the domed version
+function nut_thread_depth(type) = let(d = nut_dome(type)) d ? d[1] : nut_thickness(type); //! Max thread depth in domed version
+
+module draw_nut(od, id, t, pitch, colour, show_thread, thread_h = undef ) {
+    th = is_undef(thread_h) ? t : thread_h;
+
+    color(colour) {
+        or = od / 2;
+        fr = or * cos(30);
+
+        render_if(manifold) intersection() {
+            linear_extrude(t, convexity = 5)
+                difference() {
+                    circle(or, $fn = 6);
+
+                    if(id)
+                        circle(d = id);
+                }
+
+            if(manifold)
+                rotate_extrude()
+                    hull() {
+                        h = (or - fr) * tan(30);
+
+                        translate([0, -eps])
+                            square([fr, t + eps]);
+
+                        translate([or, h])
+                            square([eps, t - 2 * h]);
+                    }
+        }
+    }
+    if(show_thread && id)
+        female_metric_thread(id, pitch,
+            th,
+            top = th > t ? 0 : manifold ? 1 : -1,
+            bot = manifold ? 1 : -1,
+            center = false, colour = colour);
+}
+
+module nut(type, nyloc = false, brass = false, nylon = false, dome = false) { //! Draw specified nut
     thread_d = nut_size(type);
     thread_p = nut_pitch(type) ? nut_pitch(type) : metric_coarse_pitch(thread_d);
     hole_rad  = thread_d / 2;
     outer_rad = nut_radius(type);
     thickness = nut_thickness(type);
     nyloc_thickness = nut_thickness(type, true);
-    desc = nyloc ? "nyloc" : brass ? "brass" : nylon ? "nylon" : "";
-    vitamin(str("nut(", type[0], arg(nyloc, false, "nyloc"), arg(brass, false, "brass"), arg(nylon, false, "nylon"),
+    desc = nyloc ? "nyloc" : brass ? "brass" : nylon ? "nylon" : dome ? "domed" : "";
+    vitamin(str("nut(", type[0],
+                        arg(nyloc, false, "nyloc"),
+                        arg(brass, false, "brass"),
+                        arg(nylon, false, "nylon"),
+                        arg(dome,  false, "dome"),
                    "): Nut M", nut_size(type), " x ", thickness, "mm ", desc));
 
     $fs = fs; $fa = fa;
 
     colour = brass ? brass_colour : nylon ? grey(30): grey(70);
     explode(nyloc ? 10 : 0) {
+        draw_nut(outer_rad * 2, thread_d, thickness, thread_p, colour, show_threads, dome ? nut_thread_depth(type) : thickness);
+
+        fr = nut_flat_radius(type);
         color(colour) {
-            linear_extrude(thickness)
-                difference() {
-                    circle(outer_rad, $fn = 6);
-
-                    circle(hole_rad);
-                }
-
             if(nyloc)
-                translate_z(-eps)
-                    rounded_cylinder(r = outer_rad * cos(30) , h = nyloc_thickness, r2 = (nyloc_thickness - thickness) / 2, ir = hole_rad);
-        }
+                translate_z(eps)
+                    rounded_cylinder(r = outer_rad * cos(30), h = nyloc_thickness - eps, r2 = (nyloc_thickness - thickness) / 2, ir = hole_rad);
 
-        if(show_threads)
-            female_metric_thread(thread_d, thread_p, thickness, center = false, colour = colour);
+            if(dome)
+                translate_z(thickness)
+                    rotate_extrude()
+                        difference() {
+                            h = nut_dome_height(type) - thickness;
+                            r = fr - eps;
+                            rounded_corner(r, h, r);
+
+                            square([thread_d / 2, nut_thread_depth(type) - thickness]);
+                        }
+        }
 
         if(nyloc)
             translate_z(thickness)
diff --git a/vitamins/nuts.scad b/vitamins/nuts.scad
index c767dc6..03e14e9 100644
--- a/vitamins/nuts.scad
+++ b/vitamins/nuts.scad
@@ -28,25 +28,25 @@ M5_nut_depth = 4;
 M6_nut_depth = 5;
 M8_nut_depth = 6.5;
 
-//                                      s    d    t    n     w              t                  t
-//                                      c    i    h    y     a              r                  h
-//                                      r    a    i    l     s              a                  r
-//                                      e    m    c    o     h              p                  e
+//                                      s    d    t    n     w              t                  t  d    d
+//                                      c    i    h    y     a              r                  h  o    o
+//                                      r    a    i    l     s              a                  r  m    m
+//                                      e    m    c    o     h              p                  e  e    e
 //                                      w    e    k    c     e                                 d
-//                                           t    n          r              d
-//                                           e    e    t                    e                  p
-//                                           r    s    h                    p                  i
-//                                                s    k                    t                  t
-//                                                                          h                  c
-//                                                                                             h
+//                                           t    n          r              d                     h    t
+//                                           e    e    t                    e                  p  e    h
+//                                           r    s    h                    p                  i  i    r
+//                                                s    k                    t                  t  g    e
+//                                                                          h                  c  h    a
+//                                                                                             h  t    d
 M2_nut      =      ["M2_nut",           2,   4.9, 1.6, 2.4,  M2_washer,     M2_nut_trap_depth, 0];
 M2p5_nut    =      ["M2p5_nut",         2.5, 5.8, 2.2, 3.8,  M2p5_washer, M2p5_nut_trap_depth, 0];
-M3_nut      =      ["M3_nut",           3,   6.4, 2.4, 4,    M3_washer,     M3_nut_trap_depth, 0];
-M4_nut      =      ["M4_nut",           4,   8.1, 3.2, 5,    M4_washer,     M4_nut_trap_depth, 0];
-M5_nut      =      ["M5_nut",           5,   9.2, 4,   6.25, M5_washer,     M5_nut_depth,      0];
-M6_nut      =      ["M6_nut",           6,  11.5, 5,   8,    M6_washer,     M6_nut_depth,      0];
+M3_nut      =      ["M3_nut",           3,   6.4, 2.4, 4,    M3_washer,     M3_nut_trap_depth, 0, [6,   5.40]];
+M4_nut      =      ["M4_nut",           4,   8.1, 3.2, 5,    M4_washer,     M4_nut_trap_depth, 0, [8,   5.74]];
+M5_nut      =      ["M5_nut",           5,   9.2, 4,   6.25, M5_washer,     M5_nut_depth,      0, [10,  7.79]];
+M6_nut      =      ["M6_nut",           6,  11.5, 5,   8,    M6_washer,     M6_nut_depth,      0, [12,  8.29]];
 M6_half_nut =      ["M6_half_nut",      6,  11.5, 3,   8,    M6_washer,     3,                 0];
-M8_nut      =      ["M8_nut",           8,  15,   6.5, 8,    M8_washer,     M8_nut_depth,      0];
+M8_nut      =      ["M8_nut",           8,  15,   6.5, 8,    M8_washer,     M8_nut_depth,      0, [15, 11.35]];
 toggle_nut  =      ["toggle_nut",       6.1, 9.2, 1.5, 1.5,  M6_washer,     1.5,               inch(1/40)];
 
 M4_wingnut  =      ["M4_wingnut",       4,  10,   3.75,8,    M4_washer,     0, 22, 10, 6, 3];
diff --git a/vitamins/potentiometer.scad b/vitamins/potentiometer.scad
index 8554cad..5a3f61e 100644
--- a/vitamins/potentiometer.scad
+++ b/vitamins/potentiometer.scad
@@ -17,7 +17,7 @@
 // If not, see <https://www.gnu.org/licenses/>.
 //
 //! Potentiometers and rotary encoders
-include <../utils/core/core.scad>
+include <../core.scad>
 use <../utils/rounded_cylinder.scad>
 use <../utils/round.scad>
 use <../utils/thread.scad>
@@ -71,18 +71,8 @@ module pot_nut(type, washer = true) { //! Draw the nut for a potentiometer and p
                     }
 
         if(nut)
-            color(nut[2])
-                translate_z(nut_z + exploded() * 10) {
-                    linear_extrude(nut[1])
-                        difference() {
-                            circle(d = nut.x / cos(30), $fn = 6);
-
-                            circle(d =  thread_d);
-                        }
-
-                    if(show_threads && exploded())
-                        female_metric_thread(thread_d, pot_thread_p(type), nut[1], center = false, colour = nut[2]);
-                }
+            translate_z(nut_z + exploded() * 10)
+                draw_nut(nut.x / cos(30), thread_d, nut[1], pot_thread_p(type), nut[2], show_threads && exploded());
     }
 }
 
diff --git a/vitamins/screw.scad b/vitamins/screw.scad
index 9a5a9fa..befca53 100644
--- a/vitamins/screw.scad
+++ b/vitamins/screw.scad
@@ -205,8 +205,7 @@ module screw(type, length, hob_point = 0, nylon = false) { //! Draw specified sc
                     cylinder(h=2 * eps, r=socket_rad, $fn = 6);
         }
         if(head_type == hs_hex) {
-            color(colour)
-                cylinder(r = head_rad, h = head_height, $fn = 6);
+            draw_nut(head_rad * 2, 0, head_height, 0, colour, false);
 
             shaft();
         }