screw_polysink now has an alternating layer option to be more printable inverted.

The screws test now tests polysinks and has printable sample.

global_defs.scad

@@ -35,8 +35,8 @@ extrusion_width = is_undef($extrusion_width) ? 0.5    : $extrusion_width; // fil
 nozzle          = is_undef($nozzle)          ? 0.45   : $nozzle;          // 3D printer nozzle
 cnc_bit_r       = is_undef($cnc_bit_r)       ? 1.2    : $cnc_bit_r;       // minimum tool radius when milling 2D objects
 pp1_colour      = is_undef($pp1_colour)      ? [0, 146/255, 0] : $pp1_colour; // printed part colour 1, RepRap logo colour
-pp2_colour      = is_undef($pp2_colour)      ? "red"  : $pp2_colour;      // printed part colour 2
-pp3_colour      = is_undef($pp3_colour)      ? "blue" : $pp3_colour;      // printed part colour 3
+pp2_colour      = is_undef($pp2_colour)      ? "Crimson"  : $pp2_colour;  // printed part colour 2
+pp3_colour      = is_undef($pp3_colour)      ? "SteelBlue" : $pp3_colour; // printed part colour 3
 pp4_colour      = is_undef($pp4_colour)      ? "darkorange" : $pp4_colour;// printed part colour 4
 show_rays       = is_undef($show_rays)       ? false  : $show_rays;       // show camera sight lines and light direction
 show_threads    = is_undef($show_threads)    ? false  : $show_threads;    // show screw threads

libtest.scad

@@ -78,6 +78,7 @@ use <tests/opengrab.scad>
 use <tests/panel_meters.scad>
 use <tests/PCBs.scad>
 use <tests/pillars.scad>
+use <tests/press_fit.scad>
 use <tests/PSUs.scad>
 use <tests/pulleys.scad>
 use <tests/rails.scad>
@@ -137,9 +138,12 @@ cable_grommets_y = 0;
 translate([x5, cable_grommets_y])
     cable_grommets();
 
-translate([x5 + 80, cable_grommets_y])
+translate([x5 + 50, cable_grommets_y])
     ribbon_clamps();
 
+translate([x5 + 95, cable_grommets_y])
+    press_fits();
+
 translate([x5, cable_grommets_y + 60])
     fixing_blocks();
 
@@ -427,7 +431,7 @@ translate([x4 + 175, belts_y, -20])
 translate([x4, rails_y + 130])
     rails();
 
-translate([800, fans_y + 50])
+translate([770, fans_y + 50])
     cable_strips();
 
 translate([x4, kp_pillow_blocks_y])

printed/box.scad

@@ -121,11 +121,12 @@ module grill(width, height, r = 1000, poly = false, h = 0) { //! A staggered arr
 
 module box_corner_profile_2D(type) { //! The 2D shape of the corner profile.
     t = box_sheet_slot(type);
+    inset = box_corner_gap(type) + box_profile_overlap(type);
     difference() {
         union() {
             quadrant(box_hole_inset(type) + box_boss_r(type), box_boss_r(type));     // inside corner
 
-            translate([box_corner_gap(type) + box_profile_overlap(type), box_corner_gap(type) + box_profile_overlap(type)])
+            translate([inset, inset])
                 rotate(180)
                     quadrant(box_profile_overlap(type) + box_corner_rad(type), box_corner_rad(type)); // outside corner
         }
@@ -212,33 +213,39 @@ module box_bezel(type, bottom) { //! Generates top and bottom bezel STLs
     feet = bottom && box_feet(type);
     t = box_sheet_slot(type);
     outset =  box_outset(type);
+    inset = box_inset(type);
     inner_r = box_sheet_r(type);
-    foot_height = box_corner_gap(type) + sheet_thickness(box_base_sheet(type)) + washer_thickness(box_washer(type)) + screw_head_height(box_screw(type)) + box_profile_overlap(type) + 2;
+    cgap = box_corner_gap(type);
+    foot_height = cgap + sheet_thickness(box_base_sheet(type)) + washer_thickness(box_washer(type)) + screw_head_height(box_screw(type)) + box_profile_overlap(type) + 2;
     foot_length = box_corner_rad(type) * 2;
     height = box_bezel_height(type, bottom);
     foot_extension = foot_height - height;
 
     difference() {
+        w = box_width(type);
+        d = box_depth(type);
         translate_z(-box_profile_overlap(type)) difference() {
-            rounded_rectangle([box_width(type) + 2 * outset, box_depth(type) + 2 * outset, feet ? foot_height : height], box_corner_rad(type), false);
+            tw = w + 2 * outset;
+            td = d + 2 * outset;
+            rounded_rectangle([tw, td, feet ? foot_height : height], box_corner_rad(type), false);
             //
             // Remove edges between the feet
             //
             if(feet)
                 hull() {
                     translate_z(height + 0.5)
-                        cube([box_width(type) - 2 * foot_length, box_depth(type) + 2 * outset + 1, 1], center = true);
+                        cube([w - 2 * foot_length, td + 1, 1], center = true);
 
                     translate_z(foot_height + 1)
-                        cube([box_width(type) - 2 * (foot_length - foot_extension), box_depth(type) + 2 * outset + 1, 1], center = true);
+                        cube([w - 2 * (foot_length - foot_extension), td + 1, 1], center = true);
                 }
             if(feet)
                 hull() {
                     translate_z(height + 0.5)
-                        cube([box_width(type) + 2 * outset + 1, box_depth(type) - 2 * foot_length, 1], center = true);
+                        cube([tw + 1, d - 2 * foot_length, 1], center = true);
 
                     translate_z(foot_height + 1)
-                        cube([box_width(type) + 2 * outset + 1, box_depth(type) - 2 * (foot_length - foot_extension), 1], center = true);
+                        cube([tw + 1, d - 2 * (foot_length - foot_extension), 1], center = true);
                 }
         }
         //
@@ -247,28 +254,28 @@ module box_bezel(type, bottom) { //! Generates top and bottom bezel STLs
         translate_z(-box_profile_overlap(type))
             linear_extrude(2 * box_profile_overlap(type), center = true)
                 for(i = [-1, 1]) {
-                    translate([i * (box_width(type) / 2 + t / 2 - sheet_slot_clearance / 2), 0])
-                         square([t, box_depth(type) - 2 * box_corner_gap(type)], center = true);
+                    translate([i * (w + t - sheet_slot_clearance) / 2, 0])
+                         square([t, d - 2 * cgap], center = true);
 
-                    translate([0, i * (box_depth(type) / 2 + t / 2 - sheet_slot_clearance / 2)])
-                         square([box_width(type) - 2 * box_corner_gap(type), t], center = true);
+                    translate([0, i * (d + t - sheet_slot_clearance) / 2])
+                         square([w - 2 * cgap, t], center = true);
                 }
         //
         // recess for top / bottom panel
         //
-        translate_z(box_corner_gap(type))
-            rounded_rectangle([box_width(type) + bezel_clearance, box_depth(type) + bezel_clearance, height], inner_r + bezel_clearance / 2, false);
+        translate_z(cgap)
+            rounded_rectangle([w + bezel_clearance, d + bezel_clearance, height], inner_r + bezel_clearance / 2, false);
         //
         // leave plastic over the corner profiles
         //
         translate_z(-box_profile_overlap(type) - 1)
-            linear_extrude(box_profile_overlap(type) + box_corner_gap(type) + 2)
+            linear_extrude(box_profile_overlap(type) + cgap + 2)
                 union() {
                     difference() {
-                        square([box_width(type) - 2 * box_inset(type),
-                                box_depth(type) - 2 * box_inset(type)], center = true);
+                        square([w - 2 * inset,
+                                d - 2 * inset], center = true);
 
-                        box_corner_quadrants(type, box_width(type), box_depth(type));
+                        box_corner_quadrants(type, w, d);
                     }
                     box_screw_hole_positions(type)
                         poly_circle(screw_clearance_radius(box_screw(type)));
@@ -291,7 +298,9 @@ module box_bezel_section(type, bottom, rows, cols, x, y) { //! Generates interlo
     dw = bw - 2 * dowel_wall;
     dh = box_bezel_height(type, bottom) - dowel_h_wall;
 
-    dh2 = box_profile_overlap(type) + box_corner_gap(type) - dowel_h_wall;
+    profile_overlap = box_profile_overlap(type);
+
+    dh2 = profile_overlap + box_corner_gap(type) - dowel_h_wall;
 
     end_clearance = 0.5;
     module male() {
@@ -299,14 +308,14 @@ module box_bezel_section(type, bottom, rows, cols, x, y) { //! Generates interlo
             linear_extrude(dowel_length - 2 * end_clearance, center = true)
                 difference() {
                     union() {
-                        h = dh - layer_height;
+                        h1 = dh - layer_height;
                         h2 = dh2 - layer_height;
                         hull() {
-                            translate([bw / 2, h / 2])
-                                square([dw - 1, h], center = true);
+                            translate([bw / 2, h1 / 2])
+                                square([dw - 1, h1], center = true);
 
-                            translate([bw / 2, (h - 1) / 2])
-                                square([dw, h - 1], center = true);
+                            translate([bw / 2, (h1 - 1) / 2])
+                                square([dw, h1 - 1], center = true);
                         }
 
                         hull() {
@@ -318,7 +327,7 @@ module box_bezel_section(type, bottom, rows, cols, x, y) { //! Generates interlo
                         }
                     }
                     translate([bw2 / 2, 0])
-                        square([box_sheet_slot(type), 2 * box_profile_overlap(type)], center = true);
+                        square([box_sheet_slot(type), 2 * profile_overlap], center = true);
                 }
     }
 
@@ -359,7 +368,7 @@ module box_bezel_section(type, bottom, rows, cols, x, y) { //! Generates interlo
         render() difference() {
             union() {
                 clip(xmin = 0, xmax = w, ymin = 0, ymax = h)
-                    translate([tw / 2 - x * w, th / 2 - y * h, box_profile_overlap(type)])
+                    translate([tw / 2 - x * w, th / 2 - y * h, profile_overlap])
                         box_bezel(type, bottom);
 
                 if(x < cols - 1 && y == 0)
@@ -419,10 +428,14 @@ module box_bezel_section(type, bottom, rows, cols, x, y) { //! Generates interlo
     }
 }
 
-module box_screw_hole_positions(type)
+module box_screw_hole_positions(type) {
+    inset = box_hole_inset(type);
+    w = box_width(type) / 2 - inset;
+    d = box_depth(type) / 2 - inset;
     for(x = [-1, 1], y = [-1, 1])
-        translate([x * (box_width(type) / 2 - box_hole_inset(type)), y * (box_depth(type) / 2 - box_hole_inset(type))])
+        translate([x * w, y * d])
             children();
+}
 
 module box_base_blank(type) { //! Generates a 2D template for the base sheet
     dxf("box_base");

printed/drag_chain.scad

@@ -59,11 +59,11 @@ function drag_chain_z(type) = //! Outside dimension of a 180 bend
 function drag_chain(name, size, travel, wall = 1.6, bwall = 1.5, twall = 1.5, screw = M2_cap_screw, screw_lists = [[1,0,0,1],[1,0,0,1]]) = //! Constructor
     [name, size, travel, wall, bwall, twall, screw, screw_lists];
 
-function drag_chain_outer_size(type) =     //! Link outer dimensions
+function drag_chain_outer_size(type) = //! Link outer dimensions
     let(s = drag_chain_size(type), z = s.z + drag_chain_bwall(type) + drag_chain_twall(type))
         [s.x + z, s.y + 4 * drag_chain_wall(type) + 2 * clearance, z];
 
-function screw_lug_radius(screw) = //! Radius if a screw lug
+function screw_lug_radius(screw) = //! Radius of a screw lug
     corrected_radius(screw_clearance_radius(screw)) + 3.1 * extrusion_width;
 
 module screw_lug(screw, h = 0) //! Create a D shaped lug for a screw
@@ -81,23 +81,18 @@ module screw_lug(screw, h = 0) //! Create a D shaped lug for a screw
 
 function bool2int(b) = b ? 1 : 0;
 
-module drag_chain_screw_positions(type, end) {//! Place children at the screw positions, end = 0 for the start, 1 for the end
+module drag_chain_screw_positions(type, end) { //! Place children at the screw positions, end = 0 for the start, 1 for the end
     r = screw_lug_radius(drag_chain_screw(type));
     s = drag_chain_size(type);
     os = drag_chain_outer_size(type);
     R = os.z / 2;
     x0 = end ? R + norm([drag_chain_cam_x(type), R - drag_chain_twall(type)]) + clearance + r : r;
     x1 = end ? os.x - r : os.x - 2 * R - clearance - r;
-    for(i = [0 : 3]) {
-        x = i % 2;
-        y = bool2int(i > 1);
+    for(i = [0 : 3], x = [x0, x1, x0, x1][i], y = [-1, -1, 1, 1][i])
         if(drag_chain_screw_lists(type)[bool2int(end)][i])
-            translate([(x0 + x1) / 2, 0])
-                mirror([x, 0])
-                    mirror([0, y])
-                        translate([(x1 - x0) / 2,  s.y / 2 + r])
-                            children();
-    }
+            translate([x, y * (s.y / 2 + r)])
+                let($a = [180, 0, 180, 0][i])
+                    children();
 }
 
 function drag_chain_cam_x(type) = // how far the cam sticks out
@@ -108,8 +103,7 @@ function drag_chain_cam_x(type) = // how far the cam sticks out
         twall = drag_chain_twall(type)
     )   min(sqrt(max(sqr(cam_r) - sqr(r - twall), 0)), r);
 
-
-module drag_chain_link(type, start = false, end = false) { //! One link of the chain, special case for start and end
+module drag_chain_link(type, start = false, end = false, check_kids = true) { //! One link of the chain, special case for start and end
     stl(str(drag_chain_name(type), "_drag_chain_link", start ? "_start" : end ? "_end" : ""));
 
     s = drag_chain_size(type);
@@ -220,15 +214,21 @@ module drag_chain_link(type, start = false, end = false) { //! One link of the c
 
             if(start || end) {
                 drag_chain_screw_positions(type, end)
-                    screw_lug(drag_chain_screw(type), os.z);
+                    rotate($a)
+                        screw_lug(drag_chain_screw(type), os.z);
 
+                if(check_kids) {
+                    custom = drag_chain_screw_lists(type)[bool2int(end)] == [0, 0, 0, 0];
+                    assert($children == bool2int(custom), str("wrong number of children for ",  end ? "end" : "start", " STL customisation: ", $children));
+                }
                 children();
             }
         }
         if(start || end)
             translate_z(-eps)
                 drag_chain_screw_positions(type, end)
-                    poly_cylinder(r = screw_clearance_radius(drag_chain_screw(type)), h = os.z + 2 * eps, center = false);
+                    rotate($a)
+                        poly_cylinder(r = screw_clearance_radius(drag_chain_screw(type)), h = os.z + 2 * eps, center = false);
 
     }
 
@@ -250,9 +250,8 @@ module drag_chain_link(type, start = false, end = false) { //! One link of the c
     }
 }
 
-//! 1. Remove the support material from the links with side cutters.
-//! 1. Clip the links together with the special ones at the ends.
-module drag_chain_assembly(type, pos = 0) { //! Drag chain assembly
+// Need to use a wrapper because can't define nested modules in an assembly
+module _drag_chain_assembly(type, pos = 0) {
     s = drag_chain_size(type);
     x = (1 + exploded()) * s.x;
     r = drag_chain_radius(type) * x / s.x;
@@ -279,7 +278,7 @@ module drag_chain_assembly(type, pos = 0) { //! Drag chain assembly
     module link(n)                                  // Position and colour link with origin at the hinge hole
         translate([-z / 2, 0, -z / 2]) {
             stl_colour(n < 0 || n == npoints - 1 ? pp3_colour : n % 2 ? pp1_colour : pp2_colour)
-                drag_chain_link(type, start = n == -1, end = n == npoints - 1)
+                drag_chain_link(type, start = n == -1, end = n == npoints - 1, check_kids = false)
                     let($fasteners = 0) children();
             let($fasteners = 1) children();
         }
@@ -287,22 +286,36 @@ module drag_chain_assembly(type, pos = 0) { //! Drag chain assembly
     screws = drag_chain_screw_lists(type);
     custom_start = screws[0] == [0, 0, 0, 0];
     custom_end   = screws[1] == [0, 0, 0, 0];
-    assert($children == bool2int(custom_start) + bool2int(custom_end), "wrong number of children for end customisation");
-    assembly(str(drag_chain_name(type), "_drag_chain")) {
-        for(i = [0 : npoints - 2]) let(v = points[i+1] - points[i])
-            translate(points[i])
-                rotate([0, -atan2(v.z, v.x), 0])
-                    link(i);
+    assert($children == bool2int(custom_start) + bool2int(custom_end), str("wrong number of children for end customisation: ", $children));
 
-        translate(points[0] - [x, 0, 0])
-            link(-1)
-                if(custom_start)
-                    children(0);
+    for(i = [0 : npoints - 2]) let(v = points[i + 1] - points[i])
+        translate(points[i])
+            rotate([0, -atan2(v.z, v.x), 0])
+                link(i);
 
-        translate(points[npoints - 1])
-            hflip()
-                link(npoints - 1)
-                    if(custom_end)
-                        children(custom_start ? 1 : 0);
-    }
+    translate(points[0] - [x, 0, 0])
+        link(-1)
+            if(custom_start)
+                children(0);
+
+    translate(points[npoints - 1])
+        hflip()
+            link(npoints - 1)
+                if(custom_end)
+                    children(custom_start ? 1 : 0);
 }
+
+//! 1. Remove the support material from the links with side cutters.
+//! 1. Clip the links together with the special ones at the ends.
+module drag_chain_assembly(type, pos = 0)  //! Drag chain assembly
+    assembly(str(drag_chain_name(type), "_drag_chain"), big = true)
+        if($children == 2)
+            _drag_chain_assembly(type, pos) {
+                children(0);
+                children(1);
+            }
+        else if($children == 1)
+            _drag_chain_assembly(type, pos)
+                children(0);
+        else
+            _drag_chain_assembly(type, pos);

printed/press_fit.scad

@@ -0,0 +1,50 @@
+//
+// 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/>.
+//
+
+//
+//! Utility for making printed press fit connectors to join printed parts.
+//!
+//! Add solvent or glue to make a permanent fixture.
+//
+include <../core.scad>
+
+interference = 0.0;
+
+bridge_droop = layer_height; //sqrt(4 * layer_height * filament_width / PI) - layer_height;
+
+module press_fit_socket(w = 5, h = 50, horizontal = false) { //! Make a square hole to accept a peg
+    h = horizontal ? h : h + bridge_droop;
+
+    cube([w, w, 2 * h], center = true);
+}
+
+module press_fit_peg(h, w = 5, horizontal = false) {    //! Make a rounded chamfered peg for easy insertion
+    module chamfered_square(w, horizontal) {
+        h = horizontal ? w - bridge_droop : w;
+        rounded_square([w, h], 1);
+    }
+
+    translate_z(-eps)
+        linear_extrude(height = h + eps - layer_height)
+            chamfered_square(w + interference, horizontal);
+
+    translate_z(h - layer_height - eps)
+        linear_extrude(height = layer_height + eps)
+            chamfered_square(w - layer_height, horizontal);
+}

readme.md

@@ -36,13 +36,13 @@ See [usage](docs/usage.md) for requirements, installation instructions and a usa
 <tr><td> <a href = "#Displays">Displays</a> </td><td> <a href = "#Nuts">Nuts</a> </td><td> <a href = "#Spools">Spools</a> </td><td> <a href = "#Handle">Handle</a> </td><td> <a href = "#Rounded_cylinder">Rounded_cylinder</a> </td><td></td></tr>
 <tr><td> <a href = "#Extrusion_brackets">Extrusion_brackets</a> </td><td> <a href = "#O_ring">O_ring</a> </td><td> <a href = "#Springs">Springs</a> </td><td> <a href = "#PCB_mount">PCB_mount</a> </td><td> <a href = "#Rounded_polygon">Rounded_polygon</a> </td><td></td></tr>
 <tr><td> <a href = "#Extrusions">Extrusions</a> </td><td> <a href = "#Opengrab">Opengrab</a> </td><td> <a href = "#Stepper_motors">Stepper_motors</a> </td><td> <a href = "#PSU_shroud">PSU_shroud</a> </td><td> <a href = "#Sector">Sector</a> </td><td></td></tr>
-<tr><td> <a href = "#Fans">Fans</a> </td><td> <a href = "#PCB">PCB</a> </td><td> <a href = "#Swiss_clips">Swiss_clips</a> </td><td> <a href = "#Printed_box">Printed_box</a> </td><td> <a href = "#Sweep">Sweep</a> </td><td></td></tr>
-<tr><td> <a href = "#Fuseholder">Fuseholder</a> </td><td> <a href = "#PCBs">PCBs</a> </td><td> <a href = "#Toggles">Toggles</a> </td><td> <a href = "#Ribbon_clamp">Ribbon_clamp</a> </td><td> <a href = "#Thread">Thread</a> </td><td></td></tr>
-<tr><td> <a href = "#Geared_steppers">Geared_steppers</a> </td><td> <a href = "#PSUs">PSUs</a> </td><td> <a href = "#Transformers">Transformers</a> </td><td> <a href = "#SSR_shroud">SSR_shroud</a> </td><td> <a href = "#Tube">Tube</a> </td><td></td></tr>
-<tr><td> <a href = "#Green_terminals">Green_terminals</a> </td><td> <a href = "#Panel_meters">Panel_meters</a> </td><td> <a href = "#Tubings">Tubings</a> </td><td> <a href = "#Screw_knob">Screw_knob</a> </td><td></td><td></td></tr>
-<tr><td> <a href = "#Hot_ends">Hot_ends</a> </td><td> <a href = "#Pillars">Pillars</a> </td><td> <a href = "#Variacs">Variacs</a> </td><td> <a href = "#Socket_box">Socket_box</a> </td><td></td><td></td></tr>
-<tr><td> <a href = "#Hygrometer">Hygrometer</a> </td><td> <a href = "#Pin_headers">Pin_headers</a> </td><td> <a href = "#Veroboard">Veroboard</a> </td><td> <a href = "#Strap_handle">Strap_handle</a> </td><td></td><td></td></tr>
-<tr><td> <a href = "#IECs">IECs</a> </td><td> <a href = "#Pulleys">Pulleys</a> </td><td> <a href = "#Washers">Washers</a> </td><td></td><td></td><td></td></tr>
+<tr><td> <a href = "#Fans">Fans</a> </td><td> <a href = "#PCB">PCB</a> </td><td> <a href = "#Swiss_clips">Swiss_clips</a> </td><td> <a href = "#Press_fit">Press_fit</a> </td><td> <a href = "#Sweep">Sweep</a> </td><td></td></tr>
+<tr><td> <a href = "#Fuseholder">Fuseholder</a> </td><td> <a href = "#PCBs">PCBs</a> </td><td> <a href = "#Toggles">Toggles</a> </td><td> <a href = "#Printed_box">Printed_box</a> </td><td> <a href = "#Thread">Thread</a> </td><td></td></tr>
+<tr><td> <a href = "#Geared_steppers">Geared_steppers</a> </td><td> <a href = "#PSUs">PSUs</a> </td><td> <a href = "#Transformers">Transformers</a> </td><td> <a href = "#Ribbon_clamp">Ribbon_clamp</a> </td><td> <a href = "#Tube">Tube</a> </td><td></td></tr>
+<tr><td> <a href = "#Green_terminals">Green_terminals</a> </td><td> <a href = "#Panel_meters">Panel_meters</a> </td><td> <a href = "#Tubings">Tubings</a> </td><td> <a href = "#SSR_shroud">SSR_shroud</a> </td><td></td><td></td></tr>
+<tr><td> <a href = "#Hot_ends">Hot_ends</a> </td><td> <a href = "#Pillars">Pillars</a> </td><td> <a href = "#Variacs">Variacs</a> </td><td> <a href = "#Screw_knob">Screw_knob</a> </td><td></td><td></td></tr>
+<tr><td> <a href = "#Hygrometer">Hygrometer</a> </td><td> <a href = "#Pin_headers">Pin_headers</a> </td><td> <a href = "#Veroboard">Veroboard</a> </td><td> <a href = "#Socket_box">Socket_box</a> </td><td></td><td></td></tr>
+<tr><td> <a href = "#IECs">IECs</a> </td><td> <a href = "#Pulleys">Pulleys</a> </td><td> <a href = "#Washers">Washers</a> </td><td> <a href = "#Strap_handle">Strap_handle</a> </td><td></td><td></td></tr>
 <tr><td> <a href = "#Inserts">Inserts</a> </td><td></td><td> <a href = "#Wire">Wire</a> </td><td></td><td></td><td></td></tr>
 <tr><td></td><td></td><td> <a href = "#Zipties">Zipties</a> </td><td></td><td></td><td></td></tr>
 </table>
@@ -2904,6 +2904,8 @@ These items are sysmtrical, so by default the origin is in the centre but it can
 ## Screws
 Machine screws and wood screws with various head styles.
 
+For an explanation of ```screw_polysink()``` see <https://hydraraptor.blogspot.com/2020/12/sinkholes.html>.
+
 
 [vitamins/screws.scad](vitamins/screws.scad) Object definitions.
 
@@ -2930,9 +2932,10 @@ Machine screws and wood screws with various head styles.
 | Function | Description |
 |:--- |:--- |
 | ```screw_boss_diameter(type)``` | Boss big enough for nut trap and washer |
-| ```screw_head_depth(type, d)``` | How far a counter sink head will go into a straight hole diameter d |
+| ```screw_head_depth(type, d = 0)``` | How far a counter sink head will go into a straight hole diameter d |
 | ```screw_longer_than(x)``` | Returns shortest screw length longer or equal to x |
 | ```screw_nut_radius(type)``` | Radius of matching nut |
+| ```screw_polysink_r(type, z)``` | Countersink hole profile corrected for rounded staircase extrusions. |
 | ```screw_shorter_than(x)``` | Returns longest screw length shorter than or equal to x |
 
 ### Modules
@@ -2940,7 +2943,8 @@ Machine screws and wood screws with various head styles.
 |:--- |:--- |
 | ```screw(type, length, hob_point = 0, nylon = false)``` | Draw specified screw, optionally hobbed or nylon |
 | ```screw_and_washer(type, length, star = false, penny = false)``` | Screw with a washer which can be standard or penny and an optional star washer on top |
-| ```screw_countersink(type)``` | Countersink shape |
+| ```screw_countersink(type, drilled = true)``` | Countersink shape |
+| ```screw_polysink(type, h = 100, alt = false)``` | A countersink hole made from stacked polyholes for printed parts |
 
 ![screws](tests/png/screws.png)
 
@@ -2979,6 +2983,11 @@ Machine screws and wood screws with various head styles.
 |   1 | ```screw(No6_cs_screw, 30)``` |  Screw No6 cs wood x 30mm |
 |   1 | ```screw(No6_screw, 30)``` |  Screw No6 pan wood x 30mm |
 
+### Printed
+| Qty | Filename |
+| ---:|:--- |
+|   1 | polysink.stl |
+
 
 <a href="#top">Top</a>
 
@@ -4592,13 +4601,13 @@ to the assembly, for example to add inserts.
 | ```drag_chain_outer_size(type)``` | Link outer dimensions |
 | ```drag_chain_radius(type)``` | The bend radius at the pivot centres |
 | ```drag_chain_z(type)``` | Outside dimension of a 180 bend |
-| ```screw_lug_radius(screw)``` | Radius if a screw lug |
+| ```screw_lug_radius(screw)``` | Radius of a screw lug |
 
 ### Modules
 | Module | Description |
 |:--- |:--- |
 | ```drag_chain_assembly(type, pos = 0)``` | Drag chain assembly |
-| ```drag_chain_link(type, start = false, end = false)``` | One link of the chain, special case for start and end |
+| ```drag_chain_link(type, start = false, end = false, check_kids = true)``` | One link of the chain, special case for start and end |
 | ```drag_chain_screw_positions(type, end)``` | Place children at the screw positions, end = 0 for the start, 1 for the end |
 | ```screw_lug(screw, h = 0)``` | Create a D shaped lug for a screw |
 
@@ -4978,6 +4987,29 @@ The stl must be given a parameterless wrapper in the project that uses it.
 |   1 | pcb_mount_PI_IO_5.stl |
 
 
+<a href="#top">Top</a>
+
+---
+<a name="Press_fit"></a>
+## Press_fit
+Utility for making printed press fit connectors to join printed parts.
+
+Add solvent or glue to make a permanent fixture.
+
+
+[printed/press_fit.scad](printed/press_fit.scad) Implementation.
+
+[tests/press_fit.scad](tests/press_fit.scad) Code for this example.
+
+### Modules
+| Module | Description |
+|:--- |:--- |
+| ```press_fit_peg(h, w = 5, horizontal = false)``` | Make a rounded chamfered peg for easy insertion |
+| ```press_fit_socket(w = 5, h = 50, horizontal = false)``` | Make a square hole to accept a peg |
+
+![press_fit](tests/png/press_fit.png)
+
+
 <a href="#top">Top</a>
 
 ---
@@ -5829,7 +5861,7 @@ A sector of a circle between two angles.
 Utility to generate a polhedron by sweeping a 2D profile along a 3D path and utilities for generating paths.
 
 The initial orientation is the Y axis of the profile points towards the initial center of curvature, Frenet-Serret style.
-This means the first three points must not be colinear. Subsequent rotations use the minimum rotation method.
+Subsequent rotations use the minimum rotation method.
 
 The path can be open or closed. If closed sweep ensures that the start and end have the same rotation to line up.
 An additional twist around the path can be specified. If the path is closed this should be a multiple of 360.

scripts/views.py

@@ -308,8 +308,7 @@ def views(target, do_assemblies = None):
                 if printed:
                     print('### 3D Printed parts', file = doc_file)
                     keys = sorted(list(printed.keys()))
-                    for i in range(len(keys)):
-                        p = keys[i]
+                    for i, p in enumerate(keys):
                         print('%s %d x %s |' % ('\n|' if not (i % 3) else '', printed[p]["count"], p), file = doc_file, end = '')
                         if (i % 3) == 2 or i == len(printed) - 1:
                             n = (i % 3) + 1
@@ -324,8 +323,7 @@ def views(target, do_assemblies = None):
                 if routed:
                     print("### CNC Routed parts", file = doc_file)
                     keys = sorted(list(routed.keys()))
-                    for i in range(len(keys)):
-                        r = keys[i]
+                    for i, r in enumerate(keys):
                         print('%s %d x %s |' % ('\n|' if not (i % 3) else '', routed[r]["count"], r), file = doc_file, end = '')
                         if (i % 3) == 2 or i == len(routed) - 1:
                             n = (i % 3) + 1
@@ -340,8 +338,7 @@ def views(target, do_assemblies = None):
                 if sub_assemblies:
                     print("### Sub-assemblies", file = doc_file)
                     keys = sorted(list(sub_assemblies.keys()))
-                    for i in range(len(keys)):
-                        a = keys[i]
+                    for i, a in enumerate(keys):
                         print('%s %d x %s |' % ('\n|' if not (i % 3) else '', sub_assemblies[a], a), file = doc_file, end = '')
                         if (i % 3) == 2 or i == len(keys) - 1:
                             n = (i % 3) + 1

tests/press_fit.scad

@@ -0,0 +1,71 @@
+//
+// 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/>.
+//
+
+include <../printed/press_fit.scad>
+
+module press_fits()
+{
+    thickness = 2;
+    width = 20;
+    vthickness = 4;
+
+    translate([0, width + 2])
+        difference() {
+            cube([width, width, thickness]);
+
+            for(x = [0.25, 0.75])
+                for(y = [0.25, 0.75])
+                    translate([x * width, y * width])
+                        press_fit_socket();
+        }
+
+    union() {
+        cube([width, width, thickness]);
+
+        for(x = [0.25, 0.75])
+            for(y = [0.25, 0.75])
+                translate([x * width, y * width, thickness])
+                    press_fit_peg(h = thickness);
+    }
+
+    translate([width + 2, width + 2])
+        difference() {
+            cube([width, vthickness, width]);
+
+            for(x = [0.25, 0.75])
+                for(y = [0.25, 0.75])
+                    translate([x, 0, y] * width)
+                        rotate([90, 0, 0])
+                            press_fit_socket();
+        }
+
+    translate([width + 2, 0])
+        union() {
+            cube([width, width, thickness]);
+
+            for(x = [0.25, 0.75])
+                for(y = [0.25, 0.75])
+                    translate([x * width, y * width, thickness])
+                        press_fit_peg(h = vthickness, horizontal = true);
+        }
+
+}
+
+
+press_fits();

tests/rails.scad

@@ -23,6 +23,7 @@ use <../utils/layout.scad>
 use <../vitamins/nut.scad>
 
 sheet = 3;
+pos = 1; //[-1 : 0.1 : 1]
 
 module rails()
     layout([for(l = rails) carriage_width(rail_carriage(l))], 20)
@@ -33,7 +34,7 @@ module rails()
             nut = screw_nut(screw);
             washer = screw_washer(screw);
 
-            rail_assembly(rail, length, rail_travel(rail, length) / 2, $i<2 ? grey(20) : "green", $i<2 ? grey(20) : "red");
+            rail_assembly(rail, length, pos * rail_travel(rail, length) / 2, $i<2 ? grey(20) : "green", $i<2 ? grey(20) : "red");
 
             rail_screws(rail, length, sheet + nut_thickness(nut, true) + washer_thickness(washer));
 

tests/screws.scad

@@ -18,20 +18,46 @@
 //
 include <../core.scad>
 
-module screws()
-for(y = [0 : len(screw_lists) -1])
-    for(x = [0 : len(screw_lists[y]) -1]) {
-        screw = screw_lists[y][x];
-        if(screw) {
-             length = screw_head_type(screw) == hs_grub ? 6
-                    : screw_radius(screw) <= 1.5 ? 10
-                    : screw_max_thread(screw) ? screw_longer_than(screw_max_thread(screw) + 5)
-                    : 30;
-            translate([x * 20, y * 20])
-                screw(screw, length);
-        }
+module polysink_stl() {
+    stl("polysink");
+
+    cs_screws = [for(list = screw_lists, screw = list) if(screw_head_type(screw) == hs_cs_cap) screw];
+    n = len(cs_screws);
+    size = [n * 20, 20, 10];
+    difference() {
+        translate([-size.x / n / 2, $preview ? 0 : -size.y / 2, -size.z])
+            cube($preview ? [size.x, size.y / 2, size.z] : size);
+
+        for(i = [0 : n - 1])
+            let(s = cs_screws[i])
+                translate([i * 20, 0]) {
+                    screw_polysink(s, 2 * size.z + 1);
+
+                    translate_z(-size.z)
+                        screw_polysink(s, 2 * size.z + 1, alt = true);
+                }
     }
+}
+
+module screws() {
+    for(y = [0 : len(screw_lists) -1])
+        for(x = [0 : len(screw_lists[y]) -1]) {
+            screw = screw_lists[y][x];
+            if(screw) {
+                 length = screw_head_type(screw) == hs_grub ? 6
+                        : screw_radius(screw) <= 1.5 ? 10
+                        : screw_max_thread(screw) ? screw_longer_than(screw_max_thread(screw) + 5)
+                        : 30;
+                translate([x * 20, y * 20])
+                    screw(screw, length);
+            }
+        }
+        translate([80, 140])
+            polysink_stl();
+}
 
 if($preview)
     let($show_threads = true)
         screws();
+else
+    polysink_stl();

utils/rounded_polygon.scad

@@ -60,7 +60,7 @@ function rounded_polygon_length(points, tangents) = //! Calculate the length giv
                                    v1 = p1 - c,
                                    v2 = p2 - c,
                                    r = abs(corner.z),
-                                   a = acos((v1 * v2) / sqr(r))) PI * (cross(v1,v2) <= 0 ? a : 360 - a) * r / 180]
+                                   a = acos((v1 * v2) / sqr(r))) r ? PI * (cross(v1, v2) <= 0 ? a : 360 - a) * r / 180 : 0]
      )
     sumv(concat(straights, arcs));
 

utils/sweep.scad

@@ -21,7 +21,7 @@
 //! Utility to generate a polhedron by sweeping a 2D profile along a 3D path and utilities for generating paths.
 //!
 //! The initial orientation is the Y axis of the profile points towards the initial center of curvature, Frenet-Serret style.
-//! This means the first three points must not be colinear. Subsequent rotations use the minimum rotation method.
+//! Subsequent rotations use the minimum rotation method.
 //!
 //! The path can be open or closed. If closed sweep ensures that the start and end have the same rotation to line up.
 //! An additional twist around the path can be specified. If the path is closed this should be a multiple of 360.

vitamins/blowers.scad

@@ -21,7 +21,7 @@
 //                                                   n     d   p   r     r              b   i            r    r                               i    b    s    p    l    g
 //                                                   g     t   t   e     e                  s            e    e                               t         e         l
 //                                                   t     h   h         w              d                w    w                                              t
-//                                                   h                                                  h    s                                         t         t
+//                                                   h                                                   h    s                                         t         t
 RB5015 = ["RB5015", "Blower Runda RB5015",           51.3, 51, 15, 31.5, M4_cap_screw, 26, [27.3, 25.4], 4.5, [[4.3, 45.4], [47.3,7.4]],     20,   14,  1.5, 1.3, 1.2, 15];
 PE4020 = ["PE4020", "Blower Pengda Technology 4020", 40,   40, 20, 27.5, M3_cap_screw, 22, [21.5, 20  ], 3.2, [[37,3],[3,37],[37,37]],       29.3, 17,  1.7, 1.2, 1.3, 13];
 BL40x10 =["BL40x10","Square radial 4010",            40,   40,9.5, 27,   M2_cap_screw, 16, [24,   20  ], 2.4, [[2,2],[38,2],[2,38],[38,38]], 30  , 9.5, 1.5, 1.5, 1.1, 1.5];

vitamins/inserts.scad

@@ -29,7 +29,7 @@
 //                          d         d          h    d    d
 //                                         d
 //
-F1BM2   = [ "F1BM2",    4.0, 3.6, 3.2, 2,   3.0,  1.0, 3.4, 3.1 ];
+F1BM2   = [ "F1BM2",   4.0, 3.6, 3.2, 2,   3.0,  1.0, 3.4, 3.1 ];
 F1BM2p5 = [ "F1BM2p5", 5.8, 4.6, 4.0, 2.5, 3.65, 1.6, 4.4, 3.9 ];
 F1BM3   = [ "F1BM3",   5.8, 4.6, 4.0, 3,   3.65, 1.6, 4.4, 3.9 ];
 F1BM4   = [ "F1BM4",   8.2, 6.3, 5.6, 4,   5.15, 2.3, 6.0, 5.55 ];

vitamins/mains_socket.scad

@@ -116,7 +116,7 @@ module mains_socket(type) { //! Draw specified 13A socket
             cylinder(r = screw_clearance_radius(screw), h = 100, center = true);
 
             translate_z(height)
-                screw_countersink(screw);
+                screw_countersink(screw, drilled = false);
         }
     }
 }

vitamins/rail.scad

@@ -52,8 +52,9 @@ function rail_holes(type, length) = //! Number of holes in a rail given its ```l
 module rail_hole_positions(type, length, first = 0, screws = 100, both_ends = true) { //! Position children over screw holes
     pitch = rail_pitch(type);
     holes = rail_holes(type, length);
-    for(i = [first : holes - 1 - first])
-        if(i < screws || (holes - i <= screws && both_ends))
+    last = first + screws;
+    for(i = [first : holes - 1], j = holes - 1 - i)
+        if(i < last || both_ends && (j >= first && j < last))
             translate([i * pitch - length / 2 + (length - (holes - 1) * pitch) / 2, 0])
                 children();
 }
@@ -177,7 +178,6 @@ module rail_assembly(type, length, pos, carriage_end_colour = grey(20), carriage
 
     translate([pos, 0])
         carriage(rail_carriage(type), type,  carriage_end_colour, carriage_wiper_colour);
-
 }
 
 module rail_screws(type, length, thickness, screws = 100) { //! Place screws in the rail
@@ -193,6 +193,6 @@ module rail_screws(type, length, thickness, screws = 100) { //! Place screws in
             screw(end_screw, end_screw_len);
 
     translate_z(rail_screw_height(type, screw))
-        rail_hole_positions(type, length, index_screws, screws)
+        rail_hole_positions(type, length, index_screws, min(screws, rail_holes(type, length)) - 2 * index_screws)
             screw(screw, screw_len);
 }

vitamins/rails.scad

@@ -33,11 +33,11 @@ SSR15_carriage = [ 40.3, 23.3, 34, 24, 4.5, 0,  26, M4_cap_screw ];
 //
 //
 //                Wr  Hr   E    P   D    d    h
-MGN5 = [ "MGN5",  5,  3.6, 5,   15, 3.5, 2.4, 0.8, M2_cs_cap_screw, MGN5_carriage, M2_cs_cap_screw ]; // Screw holes too small for M2 heads
+MGN5 = [ "MGN5",  5,  3.6, 5,   15, 3.6, 2.4, 0.8, M2_cs_cap_screw, MGN5_carriage, M2_cs_cap_screw ]; // Screw holes too small for M2 heads
 MGN7 = [ "MGN7",  7,  5,   5,   15, 4.3, 2.4, 2.6, M2_cap_screw,    MGN7_carriage, M2_cs_cap_screw ];
 MGN9 = [ "MGN9",  9,  6,   7.5, 20, 6.0, 3.5, 3.5, M3_cap_screw,    MGN9_carriage, M3_cs_cap_screw ];
 MGN12= [ "MGN12", 12, 8,   10,  25, 6.0, 3.5, 4.5, M3_cap_screw,   MGN12_carriage, M3_cs_cap_screw ];
-MGN12H=[ "MGN12H",12, 8,    10, 25, 6.0, 3.5, 4.5, M3_cap_screw,   MGN12H_carriage,M3_cs_cap_screw ];
+MGN12H=[ "MGN12H",12, 8,   10,  25, 6.0, 3.5, 4.5, M3_cap_screw,   MGN12H_carriage,M3_cs_cap_screw ];
 MGN15= [ "MGN15", 15, 10,  10,  40, 6.0, 3.5, 5.0, M3_cap_screw,   MGN15_carriage, M3_cs_cap_screw ];
 SSR15= [ "SSR15", 15, 12.5,10,  60, 7.5, 4.5, 5.3, M4_cap_screw,   SSR15_carriage, M4_cs_cap_screw ];
 

vitamins/screw.scad

@@ -19,6 +19,8 @@
 
 //
 //! Machine screws and wood screws with various head styles.
+//!
+//! For an explanation of ```screw_polysink()``` see <https://hydraraptor.blogspot.com/2020/12/sinkholes.html>.
 //
 include <../utils/core/core.scad>
 
@@ -41,9 +43,13 @@ function screw_pilot_hole(type)       = type[11];    //! Pilot hole radius for w
 function screw_clearance_radius(type) = type[12];    //! Clearance hole radius
 function screw_nut_radius(type) = screw_nut(type) ? nut_radius(screw_nut(type)) : 0; //! Radius of matching nut
 function screw_boss_diameter(type) = max(washer_diameter(screw_washer(type)) + 1, 2 * (screw_nut_radius(type) + 3 * extrusion_width)); //! Boss big enough for nut trap and washer
-function screw_head_depth(type, d) = screw_head_height(type) ? 0 : screw_head_radius(type) - d / 2; //! How far a counter sink head will go into a straight hole diameter d
+function screw_head_depth(type, d = 0) =             //! How far a counter sink head will go into a straight hole diameter d
+    screw_head_height(type)
+        ? 0
+        : let(r = screw_radius(type)) screw_head_radius(type) - max(r, d / 2) + r / 5;
 
 function screw_longer_than(x) = x <=  5 ?  5 : //! Returns shortest screw length longer or equal to x
+                                x <=  6 ?  6 :
                                 x <=  8 ?  8 :
                                 x <= 10 ? 10 :
                                 x <= 12 ? 12 :
@@ -109,6 +115,27 @@ module screw(type, length, hob_point = 0, nylon = false) { //! Draw specified sc
                     cylinder(r = rad + eps, h = shank);
     }
 
+    module cs_head(socket_rad, socket_depth) {
+        head_t = rad / 5;
+        head_height = head_rad + head_t;
+
+        rotate_extrude()
+            difference() {
+                polygon([[0, 0], [head_rad, 0], [head_rad, -head_t], [0, -head_height]]);
+
+                translate([0, -socket_depth + eps])
+                    square([socket_rad, 10]);
+            }
+
+        translate_z(-socket_depth)
+            linear_extrude(socket_depth)
+                difference() {
+                    circle(socket_rad + 0.1);
+
+                    children();
+                }
+    }
+
     explode(length + 10) {
         if(head_type == hs_cap) {
             color(colour) {
@@ -201,63 +228,76 @@ module screw(type, length, hob_point = 0, nylon = false) { //! Draw specified sc
         }
 
         if(head_type == hs_cs) {
-            head_height = head_rad;
             socket_rad = 0.6 * head_rad;
             socket_depth = 0.3 * head_rad;
             socket_width = 1;
-            color(colour) {
-                rotate_extrude()
-                    difference() {
-                        polygon([[0, 0], [head_rad, 0], [0, -head_height]]);
+            color(colour)
+                cs_head(socket_rad, socket_depth) {
+                    square([2 * socket_rad, socket_width], center = true);
+                    square([socket_width, 2 * socket_rad], center = true);
+                }
 
-                        translate([0, -socket_depth + eps])
-                            square([socket_rad + 0.1, 10]);
-                    }
-
-                translate_z(-socket_depth)
-                    linear_extrude(socket_depth)
-                        difference() {
-                            circle(socket_rad + 0.1);
-
-                            square([2 * socket_rad, socket_width], center = true);
-                            square([socket_width, 2 * socket_rad], center = true);
-                        }
-            }
             shaft(socket_depth);
         }
 
         if(head_type == hs_cs_cap) {
-            head_height = head_rad;
-            color(colour) {
-                rotate_extrude()
-                    difference() {
-                        polygon([[0, 0], [head_rad, 0], [0, -head_height]]);
+            color(colour)
+                cs_head(socket_rad, socket_depth)
+                    circle(socket_rad, $fn = 6);
 
-                        translate([0, -socket_depth + eps])
-                            square([socket_rad, 10]);
-                    }
-
-                translate_z(-socket_depth)
-                    linear_extrude(socket_depth)
-                        difference() {
-                            circle(socket_rad + 0.1);
-
-                            circle(socket_rad, $fn = 6);
-                        }
-            }
             shaft(socket_depth);
         }
     }
 }
 
-module screw_countersink(type) { //! Countersink shape
+module screw_countersink(type, drilled = true) { //! Countersink shape
     head_type   = screw_head_type(type);
     head_rad    = screw_head_radius(type);
-    head_height = head_rad;
+    rad = screw_radius(type);
+    head_t = rad / 5;
+    head_height = head_rad + head_t;
 
     if(head_type == hs_cs || head_type == hs_cs_cap)
         translate_z(-head_height)
-             cylinder(h = head_height, r1 = 0, r2 = head_rad);
+            if(drilled)
+                cylinder(h = head_height + eps, r1 = 0, r2 = head_rad + head_t);
+            else
+                intersection() {
+                    cylinder(h = head_height + eps, r1 = 0, r2 = head_rad + head_t);
+
+                    cylinder(h = head_height + eps, r = head_rad + eps);
+                }
+}
+
+function screw_polysink_r(type, z) = //! Countersink hole profile corrected for rounded staircase extrusions.
+    let(rad = screw_radius(type),
+        head_t = rad / 5,
+        head_rad = screw_head_radius(type)
+    )
+    limit(head_rad + head_t - z + (sqrt(2) - 1) * layer_height / 2, screw_clearance_radius(type), head_rad);
+
+module screw_polysink(type, h = 100, alt = false) { //! A countersink hole made from stacked polyholes for printed parts
+    head_depth = screw_head_depth(type);
+    assert(head_depth, "Not a countersunk screw");
+    layers = ceil(head_depth / layer_height);
+    rmin = screw_clearance_radius(type);
+    sides = sides(rmin);
+    lh = layer_height + eps;
+    render(convexity = 5)
+        for(side = [0, 1]) mirror([0, 0, side]) {
+            for(i = [0 : layers - 1])
+                translate_z(i * layer_height) {
+                    r = screw_polysink_r(type, i * layer_height + layer_height / 2);
+                    if(alt)
+                        rotate(i % 2 == layers % 2 ? 180 / sides : 0)
+                            poly_cylinder(r = r, h = lh, center = false, sides = sides);
+                    else
+                        poly_cylinder(r = r, h = lh, center = false);
+                }
+
+            translate_z(layers * layer_height)
+                poly_cylinder(r = rmin, h = h / 2 - layers * layer_height, center = false);
+        }
 }
 
 module screw_and_washer(type, length, star = false, penny = false) { //! Screw with a washer which can be standard or penny and an optional star washer on top

vitamins/screws.scad

@@ -107,14 +107,14 @@ No6_screw        = ["No6", "No6 pan wood",      hs_pan, 3.5, 6.7, 2.2,    0,   0
 No6_cs_screw     = ["No6_cs", "No6 cs wood",    hs_cs,  3.5, 7.0, 0,      0,   0, 0,   M4_washer, false,    No6_pilot_radius, No6_clearance_radius];
 
 screw_lists = [
-[ M2_cap_screw, M2p5_cap_screw, M3_cap_screw,    M4_cap_screw, M5_cap_screw, M6_cap_screw, M8_cap_screw],
-[ 0,            0,              M3_low_cap_screw],
-[ 0,            0,              M3_hex_screw,    M4_hex_screw, M5_hex_screw, M6_hex_screw, M8_hex_screw],
-[ 0,            M2p5_pan_screw, M3_pan_screw,    M4_pan_screw, M5_pan_screw, M6_pan_screw, No632_pan_screw],
-[ 0,            No2_screw,      No4_screw,       No6_screw,    No6_cs_screw],
-[ 0,            M2_cs_cap_screw,M3_cs_cap_screw, M4_cs_cap_screw],
-[ 0,            M2_dome_screw,  M3_dome_screw,   M4_dome_screw],
-[ 0,            0,              M3_grub_screw,   M4_grub_screw]
+[ M2_cap_screw,    M2p5_cap_screw, M3_cap_screw,    M4_cap_screw, M5_cap_screw, M6_cap_screw, M8_cap_screw],
+[ 0,               0,              M3_low_cap_screw],
+[ M2_cs_cap_screw, 0,              M3_cs_cap_screw, M4_cs_cap_screw],
+[ M2_dome_screw,   0,              M3_dome_screw,   M4_dome_screw],
+[ 0,               0,              M3_hex_screw,    M4_hex_screw, M5_hex_screw, M6_hex_screw, M8_hex_screw],
+[ 0,               M2p5_pan_screw, M3_pan_screw,    M4_pan_screw, M5_pan_screw, M6_pan_screw, No632_pan_screw],
+[ No2_screw,       0,              No4_screw,       No6_screw,    No6_cs_screw],
+[ 0,               0,              M3_grub_screw,   M4_grub_screw]
 ];
 
 use <screw.scad>

vitamins/sheets.scad

@@ -38,7 +38,7 @@ PMMA8     = [ "PMMA8",     "Sheet acrylic",           8, [1,   1,   1,   0.5  ],
 PMMA10    = [ "PMMA10",    "Sheet acrylic",          10, [1,   1,   1,   0.5  ], false];   // ~3/8"
 glass2    = [ "glass2",    "Sheet glass",             2, [1,   1,   1,   0.25 ], false];
 DiBond    = [ "DiBond",    "Sheet DiBond",            3, [0.2, 0.2, 0.2, 1    ], false];
-DiBond6   = [ "DiBond6",   "Sheet DiBond",            6, "RoyalBlue",            false];
+DiBond6   = [ "DiBond6",   "Sheet DiBond",            6, [0.2, 0.2, 0.2, 1    ], false];
 Cardboard = [ "Cardboard", "Corrugated cardboard",    5, [0.8, 0.6, 0.3, 1    ], false];
 FoilTape  = [ "FoilTape",  "Aluminium foil tape",   0.05,[0.9, 0.9, 0.9, 1    ], false];
 Foam20    = [ "Foam20",    "Foam sponge",             20,[0.3, 0.3, 0.3, 1    ], true];