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

The screws test now tests polysinks and has printable sample.

readme.md

@@ -2944,7 +2944,7 @@ For an explanation of ```screw_polysink()``` see <https://hydraraptor.blogspot.c
 | ```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, drilled = true)``` | Countersink shape |
-| ```screw_polysink(type)``` | A countersink hole made from stacked polyholes for printed parts |
+| ```screw_polysink(type, h = 100, alt = false)``` | A countersink hole made from stacked polyholes for printed parts |
 
 ![screws](tests/png/screws.png)
 
@@ -2983,6 +2983,11 @@ For an explanation of ```screw_polysink()``` see <https://hydraraptor.blogspot.c
 |   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>
 

tests/screws.scad

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

vitamins/screw.scad

@@ -276,15 +276,28 @@ function screw_polysink_r(type, z) = //! Countersink hole profile corrected for
     )
     limit(head_rad + head_t - z + (sqrt(2) - 1) * layer_height / 2, screw_clearance_radius(type), head_rad);
 
-module screw_polysink(type) { //! A countersink hole made from stacked polyholes for printed parts
+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);
-    for(i = [0 : layers - 1], side = [-1, 1])
+    rmin = screw_clearance_radius(type);
-        translate_z(side * (i + 0.5) * layer_height)
+    sides = sides(rmin);
-            poly_cylinder(r = screw_polysink_r(type, i * layer_height + layer_height / 2), h = layer_height + 2 * eps, center = true);
+    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);
+                }
 
-    poly_cylinder(r = screw_clearance_radius(type), h = 100, center = true);
+            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],
+[ 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_low_cap_screw],
-[ 0,            0,              M3_hex_screw,    M4_hex_screw, M5_hex_screw, M6_hex_screw, M8_hex_screw],
+[ M2_cs_cap_screw, 0,              M3_cs_cap_screw, M4_cs_cap_screw],
-[ 0,            M2p5_pan_screw, M3_pan_screw,    M4_pan_screw, M5_pan_screw, M6_pan_screw, No632_pan_screw],
+[ M2_dome_screw,   0,              M3_dome_screw,   M4_dome_screw],
-[ 0,            No2_screw,      No4_screw,       No6_screw,    No6_cs_screw],
+[ 0,               0,              M3_hex_screw,    M4_hex_screw, M5_hex_screw, M6_hex_screw, M8_hex_screw],
-[ 0,            M2_cs_cap_screw,M3_cs_cap_screw, M4_cs_cap_screw],
+[ 0,               M2p5_pan_screw, M3_pan_screw,    M4_pan_screw, M5_pan_screw, M6_pan_screw, No632_pan_screw],
-[ 0,            M2_dome_screw,  M3_dome_screw,   M4_dome_screw],
+[ No2_screw,       0,              No4_screw,       No6_screw,    No6_cs_screw],
-[ 0,            0,              M3_grub_screw,   M4_grub_screw]
+[ 0,               0,              M3_grub_screw,   M4_grub_screw]
 ];
 
 use <screw.scad>