mdw@git.distorted.org.uk Git - scad/blob - discpick-tensioner.scad

   1 /* -*-c-*-
   2  *
   3  * Replacement tensioner for the Sparrows disc-detainer picking tool
   4  *
   5  * (c) 2023 Mark Wooding
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This program is free software: you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 3 of the License, or (at
  13  * your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful, but
  16  * WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  22  */
  23
  24 /*----- Configuration -----------------------------------------------------*/
  25
  26 /* Overall scaling. */
  27 MM = 1;
  28
  29 /* Curvature quality. */
  30 $fa = 0.1;
  31 $fs = 0.2*MM;
  32
  33 /* A `large enough' length; effectively infinite. */
  34 BIG = 50*MM;
  35
  36 /* Dimensions. */
  37 STOCK_DIAM = 5.5*MM;                    /* stock diemeter */
  38 STOCK_LENGTH = 35*MM;                   /* total stock length */
  39 SQUARE_SIDE = 4.5*MM;                   /* square section side */
  40 SQUARE_LENGTH = 26*MM;                  /* length of square section */
  41 DRILL_DIAM = 1.6*MM;                    /* hole diameter for picking tip */
  42 PRONG_DIAM = 3.3*MM;                    /* hole diameter to form prongs */
  43 PRONG_DEPTH = 6*MM;                     /* depth of prong hole */
  44 PRONG_LENGTH = 4.5*MM;                  /* prong length */
  45 PRONG_HEIGHT = 2.5*MM;                  /* prong height */
  46
  47 /*----- The main object ---------------------------------------------------*/
  48
  49 difference() {
  50
  51   /* Start with a cylinder. */
  52   rotate([0, 90, 0])
  53     cylinder(h = STOCK_LENGTH, r = STOCK_DIAM/2);
  54
  55   /* And now we cut things away. */
  56   union() {
  57
  58     /* First, put the flat sides so that the tensioning arms can grip it. */
  59     for (theta = [0 : 90 : 270])
  60       rotate([theta, 0, 0])
  61         translate([0, -BIG/2, SQUARE_SIDE/2])
  62         cube([SQUARE_LENGTH, BIG, BIG]);
  63
  64     /* Drill a hole all the way through for the picking tip. */
  65     rotate([0, 90, 0])
  66       cylinder(h = BIG, r = DRILL_DIAM/2);
  67
  68     /* Drill a hole in the end to form the gap between the prongs. */
  69     translate([STOCK_LENGTH - PRONG_DEPTH, 0, 0])
  70       rotate([0, 90, 0])
  71       cylinder(h = BIG, r = PRONG_DIAM/2);
  72
  73     /* Finally, shave off top and bottom to form the prongs themselves. */
  74     for (theta = [0 : 180 : 180])
  75       rotate([theta, 0, 0])
  76         translate([STOCK_LENGTH - PRONG_LENGTH,
  77                    -BIG/2,
  78                    (STOCK_DIAM - PRONG_HEIGHT)/2])
  79         cube(BIG);
  80   }
  81 }