discpick-tensioner.scad: Improved tensioning component with longer prongs.

diff --git a/Makefile b/Makefile
index 2e4f2f1..8bf0ff3 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -34,6 +34,7 @@ OPENSCAD               = openscad
 
 ## Main list of models.
 MODELS                 += discpick-collar.scad
+MODELS                 += discpick-tensioner.scad
 
 ## Building models.
 CLEANFILES             += *.stl

diff --git a/discpick-tensioner.pdf b/discpick-tensioner.pdf
new file mode 100644 (file)
index 0000000..0b928a3
Binary files /dev/null and b/discpick-tensioner.pdf differ

diff --git a/discpick-tensioner.scad b/discpick-tensioner.scad
new file mode 100644 (file)
index 0000000..42e6626
--- /dev/null
+++ b/discpick-tensioner.scad
@@ -0,0 +1,81 @@
+/* -*-c-*-
+ *
+ * Replacement tensioner for the Sparrows disc-detainer picking tool
+ *
+ * (c) 2023 Mark Wooding
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * This program 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.
+ *
+ * This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/*----- Configuration -----------------------------------------------------*/
+
+/* Overall scaling. */
+MM = 1;
+
+/* Curvature quality. */
+$fa = 0.1;
+$fs = 0.2*MM;
+
+/* A `large enough' length; effectively infinite. */
+BIG = 50*MM;
+
+/* Dimensions. */
+STOCK_DIAM = 5.5*MM;                   /* stock diemeter */
+STOCK_LENGTH = 35*MM;                  /* total stock length */
+SQUARE_SIDE = 4.5*MM;                  /* square section side */
+SQUARE_LENGTH = 26*MM;                 /* length of square section */
+DRILL_DIAM = 1.6*MM;                   /* hole diameter for picking tip */
+PRONG_DIAM = 3.3*MM;                   /* hole diameter to form prongs */
+PRONG_DEPTH = 6*MM;                    /* depth of prong hole */
+PRONG_LENGTH = 4.5*MM;                 /* prong length */
+PRONG_HEIGHT = 2.5*MM;                 /* prong height */
+
+/*----- The main object ---------------------------------------------------*/
+
+difference() {
+
+  /* Start with a cylinder. */
+  rotate([0, 90, 0])
+    cylinder(h = STOCK_LENGTH, r = STOCK_DIAM/2);
+
+  /* And now we cut things away. */
+  union() {
+
+    /* First, put the flat sides so that the tensioning arms can grip it. */
+    for (theta = [0 : 90 : 270])
+      rotate([theta, 0, 0])
+       translate([0, -BIG/2, SQUARE_SIDE/2])
+       cube([SQUARE_LENGTH, BIG, BIG]);
+
+    /* Drill a hole all the way through for the picking tip. */
+    rotate([0, 90, 0])
+      cylinder(h = BIG, r = DRILL_DIAM/2);
+
+    /* Drill a hole in the end to form the gap between the prongs. */
+    translate([STOCK_LENGTH - PRONG_DEPTH, 0, 0])
+      rotate([0, 90, 0])
+      cylinder(h = BIG, r = PRONG_DIAM/2);
+
+    /* Finally, shave off top and bottom to form the prongs themselves. */
+    for (theta = [0 : 180 : 180])
+      rotate([theta, 0, 0])
+       translate([STOCK_LENGTH - PRONG_LENGTH,
+                  -BIG/2,
+                  (STOCK_DIAM - PRONG_HEIGHT)/2])
+       cube(BIG);
+  }
+}