From ca1b34e9cad5d82bd878fa4ebf439c0fbdad7f77 Mon Sep 17 00:00:00 2001
From: Chris Palmer <nop.head@gmail.com>
Date: Mon, 22 Mar 2021 16:11:51 +0000
Subject: [PATCH] Added `sink` parameter to `screw_polysink()` to recess the
 head.

---
 CHANGELOG.md        | 3 +++
 readme.md           | 2 +-
 tests/screws.scad   | 8 ++++++--
 vitamins/screw.scad | 6 +++---
 4 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 109ec19..86128e8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,9 @@
 This changelog is generated by `changelog.py` using manually added semantic version tags to classify commits as breaking changes, additions or fixes.
 
 
+#### [v15.1.1](https://github.com/nophead/NopSCADlib/releases/tag/v15.1.1 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v15.1.0...v15.1.1 "diff with v15.1.0")
+*   2021-03-22 [`cbab9ce`](https://github.com/nophead/NopSCADlib/commit/cbab9cea028a204032a91729597572a39ed893a2 "show commit") [C.P.](# "Chris Palmer") Fixed `M6_cs_cap_screw`.
+
 ### [v15.1.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.1.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.0.1...v15.1.0 "diff with v15.0.1")
 *   2021-03-21 [`4aa7dbb`](https://github.com/nophead/NopSCADlib/commit/4aa7dbb416773e42b2b5f77b345f18fcd4d2ae2c "show commit") [C.P.](# "Chris Palmer") Added `M6_cs_cap_screw`.
 
diff --git a/readme.md b/readme.md
index d19d6de..6a5c2b1 100644
--- a/readme.md
+++ b/readme.md
@@ -3005,7 +3005,7 @@ For an explanation of `screw_polysink()` see <https://hydraraptor.blogspot.com/2
 | `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, h = 100, alt = false)` | A countersink hole made from stacked polyholes for printed parts |
+| `screw_polysink(type, h = 100, alt = false, sink = 0)` | A countersink hole made from stacked polyholes for printed parts, default is flush, `sink` can be used to recess the head |
 
 ![screws](tests/png/screws.png)
 
diff --git a/tests/screws.scad b/tests/screws.scad
index 7da801a..97dabc7 100644
--- a/tests/screws.scad
+++ b/tests/screws.scad
@@ -16,6 +16,10 @@
 // You should have received a copy of the GNU General Public License along with NopSCADlib.
 // If not, see <https://www.gnu.org/licenses/>.
 //
+
+// Extra countersink depth
+sink = 0; // [0 : 0.05: 1.0]
+
 include <../core.scad>
 
 module polysink_stl() {
@@ -32,9 +36,9 @@ module polysink_stl() {
             let(s = cs_screws[i])
                 translate([i * 20, 0]) {
                     translate_z(size.z)
-                        screw_polysink(s, 2 * size.z + 1);
+                        screw_polysink(s, 2 * size.z + 1, sink = sink);
 
-                    screw_polysink(s, 2 * size.z + 1, alt = true);
+                    screw_polysink(s, 2 * size.z + 1, alt = true, sink = sink);
                 }
     }
 }
diff --git a/vitamins/screw.scad b/vitamins/screw.scad
index 8cb9dba..5575453 100644
--- a/vitamins/screw.scad
+++ b/vitamins/screw.scad
@@ -284,10 +284,10 @@ 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, h = 100, alt = false) { //! A countersink hole made from stacked polyholes for printed parts
+module screw_polysink(type, h = 100, alt = false, sink = 0) { //! A countersink hole made from stacked polyholes for printed parts, default is flush, `sink` can be used to recess the head
     head_depth = screw_head_depth(type);
     assert(head_depth, "Not a countersunk screw");
-    layers = ceil(head_depth / layer_height);
+    layers = ceil((head_depth + sink) / layer_height);
     rmin = screw_clearance_radius(type);
     sides = sides(rmin);
     lh = layer_height + eps;
@@ -295,7 +295,7 @@ module screw_polysink(type, h = 100, alt = false) { //! A countersink hole made
         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);
+                    r = screw_polysink_r(type, i * layer_height + layer_height / 2 - sink);
                     if(alt)
                         rotate(i % 2 == layers % 2 ? 180 / sides : 0)
                             poly_cylinder(r = r, h = lh, center = false, sides = sides);