acorn/acorn-threads.scad

   1 // Threads for acorn model
   2 // Copyright (c) 2017 Clinton Ebadi <clinton@unknownlamer.org>
   3
   4 use <screw_threads.scad> // http://www.thingiverse.com/thing:1686322
   5
   6 AUTO_CALCULATE = -1;
   7
   8 acorn_parts = [ "body", "cap", "gasket" ];
   9
  10 internal_thread_tolerance = 0.3;
  11 external_thread_tolerance = 0.2;
  12 thread_angle = 50;
  13
  14
  15 function contains (x, lst) = len([ for (i = lst) if (x == i) i]) > 0;
  16
  17 // dome module from https://github.com/Sembiance/common/blob/master/openscad/dome.scad, Public Domain
  18 module dome(d=5, h=2, hollow=false, wallWidth=0.5) {
  19      sphereRadius = (pow(h, 2) + pow((d/2), 2) ) / (2*h);
  20      translate([0, 0, (sphereRadius-h)*-1]) {
  21           difference() {
  22                sphere(sphereRadius);
  23                translate([0, 0, -h]) cube([2*sphereRadius, 2*sphereRadius, 2*sphereRadius], center=true);
  24                if(hollow) sphere(sphereRadius-wallWidth);
  25           }
  26      }
  27 }
  28
  29 module acorn (thread_pitch = 3.0,
  30               thread_size = 2.5,
  31               thread_height = 3.5,
  32               thread_tooth_height = AUTO_CALCULATE,
  33
  34               inner_d = 24.5,
  35               base_height = AUTO_CALCULATE,
  36               wall_thickness = AUTO_CALCULATE,
  37               outer_d = AUTO_CALCULATE,
  38               dome_h = AUTO_CALCULATE,
  39
  40               keychain = true) {
  41
  42      // derived settings
  43      wall_thickness = (wall_thickness == AUTO_CALCULATE) ? thread_size : wall_thickness;
  44      outer_d = (outer_d == AUTO_CALCULATE) ? inner_d + wall_thickness*2 : outer_d;
  45      thread_tooth_height = (thread_tooth_height == AUTO_CALCULATE) ? ((thread_pitch - 0.4 > 0) ? thread_pitch - 0.4 : thread_pitch) : thread_tooth_height;
  46      base_height = (base_height == AUTO_CALCULATE) ? inner_d : base_height;
  47
  48      echo ("outer_d = ", outer_d);
  49
  50
  51      module acorn_thread (outer_d = outer_d, internal = false, ring = true) {
  52           if (internal) {
  53                outer_ring_d = outer_d+max(thread_size, wall_thickness)+1;
  54                echo ("outer ring = ", outer_ring_d);
  55                ScrewHole (outer_diam=outer_d, height = thread_height, pitch = thread_pitch, tooth_height = thread_tooth_height, tooth_angle = thread_angle, tolerance=internal_thread_tolerance) {
  56                     if (ring) cylinder (d = outer_ring_d, h = thread_height);
  57                }
  58           }
  59
  60           if (!internal) {
  61                difference () {
  62                     ScrewThread (outer_diam=outer_d, height = thread_height, pitch = thread_pitch, tooth_height = thread_tooth_height, tooth_angle = thread_angle, tolerance=external_thread_tolerance);
  63                     cylinder (d = outer_d-wall_thickness-thread_size-0.01, h = thread_height * 4, center=true);
  64                }
  65           }
  66      }
  67
  68      module nut_body (h = base_height, d = outer_d, nub = false) {
  69           translate ([0 ,0, h]) {
  70                intersection () {
  71                     union () {
  72                          resize ([d, d, h*2]) sphere (d=h*2);
  73                          if (nub) {
  74                               translate ([0, d/2-wall_thickness/2, -thread_height]) sphere (d=wall_thickness*2, $fs = 0.1);
  75                          }
  76                     }
  77                     translate ([0 ,0, -h/2]) cube ([d*2, d*2, h], center=true);
  78                }
  79           }
  80      }
  81
  82      module nut () {
  83           difference () {
  84                nut_body ();
  85                translate ([0, 0, wall_thickness + 0.01])  nut_body (d=outer_d-wall_thickness*2, nub=false);
  86           }
  87
  88           translate ([0, 0, base_height-0.1]) acorn_thread (outer_d = outer_d);
  89      }
  90
  91
  92      module cap_keychain_holes (hole_d=3, spacing=12) {
  93           h=100;
  94           translate ([-spacing/2, 0, 0]) cylinder (d=hole_d, h=h, $fs=0.1);
  95           translate ([spacing/2, 0, 0]) cylinder (d=hole_d, h=h, $fs=0.1);
  96      }
  97
  98      module cap (model="3D/RaleighAcorn_Filled_simple.stl", native_d = 168) {
  99           scale_f = outer_d / native_d; //168;
 100           echo ("scale_f = ", scale_f);
 101           difference () {
 102                scale ([scale_f, scale_f, scale_f]) {
 103                     difference () {
 104                          union () {
 105                               translate ([0, 0, -1]) import (model);
 106                               echo ("h = ", thread_height/scale_f);
 107                          }
 108                          // todo: only makes sense for RaleighAcorn, fix in original model...
 109                          translate ([0, 0, -0.51]) cube ([200, 200, 1], center=true);
 110                     }
 111                }
 112                if (keychain) cap_keychain_holes ();
 113
 114                // hollow the cap out (make parametric later, this is pretty ugly now, but calc seems to be ok for RaleighAcorn)
 115                diam_to_height_ratio = 3.2;
 116                dome_h = (dome_h == AUTO_CALCULATE) ? outer_d / diam_to_height_ratio - thread_height : dome_h;
 117                echo ("dome_h = ", dome_h);
 118                difference () {
 119                     translate ([0, 0, thread_height-0.01]) dome (d=outer_d, h=dome_h);
 120                }
 121
 122
 123                if (thread_height != 0) {
 124                     translate ([0, 0, -0.01]) acorn_thread (internal = true, ring = false);
 125                }
 126           }
 127      }
 128
 129      module gasket (gasket_height=0.9) {
 130           cylinder (d = outer_d, h = gasket_height, center=true);
 131      }
 132
 133      module nuts () {
 134           if (contains ("body", acorn_parts))
 135                translate ([outer_d+10, 0, 0,])  nut ();
 136           if (contains ("cap", acorn_parts))
 137                cap (native_d=167);//model="3D/RaleighAcorn_ExaggeratedCap_Decimated.stl", native_d = 178);
 138           if (contains ("gasket", acorn_parts))
 139               translate ([-(outer_d+10), 0, 0,])  gasket ();
 140      }
 141
 142      nuts ();
 143 }
 144
 145 //$fs = 1;
 146 //$fa = 1;
 147
 148 acorn_parts = [ "cap"];
 149
 150 //acorn ();
 151 huge_acorn ();
 152 module medium_acorn () {
 153      // older slightly larger model.
 154      acorn (inner_d = 26, base_height=20);
 155 }
 156
 157 module huge_acorn () {
 158      acorn (inner_d=100, base_height=80,
 159             thread_size=4, thread_pitch=4, thread_height=8,
 160             keychain=false);
 161 }