+++ /dev/null
-/*\r
- * ISO-standard metric threads, following this specification:\r
- * http://en.wikipedia.org/wiki/ISO_metric_screw_thread\r
- *\r
- * Copyright 2020 Dan Kirshner - dan_kirshner@yahoo.com\r
- * This program is free software: you can redistribute it and/or modify\r
- * it under the terms of the GNU General Public License as published by\r
- * the Free Software Foundation, either version 3 of the License, or\r
- * (at your option) any later version.\r
- *\r
- * This program is distributed in the hope that it will be useful,\r
- * but WITHOUT ANY WARRANTY; without even the implied warranty of\r
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the\r
- * GNU General Public License for more details.\r
- *\r
- * See <http://www.gnu.org/licenses/>.\r
- *\r
- * Version 2.4. 2019-07-14 Add test option - do not render threads.\r
- * Version 2.3. 2017-08-31 Default for leadin: 0 (best for internal threads).\r
- * Version 2.2. 2017-01-01 Correction for angle; leadfac option. (Thanks to\r
- * Andrew Allen <a2intl@gmail.com>.)\r
- * Version 2.1. 2016-12-04 Chamfer bottom end (low-z); leadin option.\r
- * Version 2.0. 2016-11-05 Backwards compatibility (earlier OpenSCAD) fixes.\r
- * Version 1.9. 2016-07-03 Option: tapered.\r
- * Version 1.8. 2016-01-08 Option: (non-standard) angle.\r
- * Version 1.7. 2015-11-28 Larger x-increment - for small-diameters.\r
- * Version 1.6. 2015-09-01 Options: square threads, rectangular threads.\r
- * Version 1.5. 2015-06-12 Options: thread_size, groove.\r
- * Version 1.4. 2014-10-17 Use "faces" instead of "triangles" for polyhedron\r
- * Version 1.3. 2013-12-01 Correct loop over turns -- don't have early cut-off\r
- * Version 1.2. 2012-09-09 Use discrete polyhedra rather than linear_extrude ()\r
- * Version 1.1. 2012-09-07 Corrected to right-hand threads!\r
- */\r
-\r
-// Examples.\r
-//\r
-// Standard M8 x 1.\r
-// metric_thread (diameter=8, pitch=1, length=4);\r
-\r
-// Square thread.\r
-// metric_thread (diameter=8, pitch=1, length=4, square=true);\r
-\r
-// Non-standard: long pitch, same thread size.\r
-//metric_thread (diameter=8, pitch=4, length=4, thread_size=1, groove=true);\r
-\r
-// Non-standard: 20 mm diameter, long pitch, square "trough" width 3 mm,\r
-// depth 1 mm.\r
-//metric_thread (diameter=20, pitch=8, length=16, square=true, thread_size=6,\r
-// groove=true, rectangle=0.333);\r
-\r
-// English: 1/4 x 20.\r
-//english_thread (diameter=1/4, threads_per_inch=20, length=1);\r
-\r
-// Tapered. Example -- pipe size 3/4" -- per:\r
-// http://www.engineeringtoolbox.com/npt-national-pipe-taper-threads-d_750.html\r
-// english_thread (diameter=1.05, threads_per_inch=14, length=3/4, taper=1/16);\r
-\r
-// Thread for mounting on Rohloff hub.\r
-//difference () {\r
-// cylinder (r=20, h=10, $fn=100);\r
-//\r
-// metric_thread (diameter=34, pitch=1, length=10, internal=true, n_starts=6);\r
-//}\r
-\r
-\r
-// ----------------------------------------------------------------------------\r
-function segments (diameter) = min (50, max (ceil (diameter*6), 25));\r
-\r
-\r
-// ----------------------------------------------------------------------------\r
-// diameter - outside diameter of threads in mm. Default: 8.\r
-// pitch - thread axial "travel" per turn in mm. Default: 1.\r
-// length - overall axial length of thread in mm. Default: 1.\r
-// internal - true = clearances for internal thread (e.g., a nut).\r
-// false = clearances for external thread (e.g., a bolt).\r
-// (Internal threads should be "cut out" from a solid using\r
-// difference ()). Default: false.\r
-// n_starts - Number of thread starts (e.g., DNA, a "double helix," has\r
-// n_starts=2). See wikipedia Screw_thread. Default: 1.\r
-// thread_size - (non-standard) axial width of a single thread "V" - independent\r
-// of pitch. Default: same as pitch.\r
-// groove - (non-standard) true = subtract inverted "V" from cylinder\r
-// (rather thanadd protruding "V" to cylinder). Default: false.\r
-// square - true = square threads (per\r
-// https://en.wikipedia.org/wiki/Square_thread_form). Default:\r
-// false.\r
-// rectangle - (non-standard) "Rectangular" thread - ratio depth/(axial) width\r
-// Default: 0 (standard "v" thread).\r
-// angle - (non-standard) angle (deg) of thread side from perpendicular to\r
-// axis (default = standard = 30 degrees).\r
-// taper - diameter change per length (National Pipe Thread/ANSI B1.20.1\r
-// is 1" diameter per 16" length). Taper decreases from 'diameter'\r
-// as z increases. Default: 0 (no taper).\r
-// leadin - 0 (default): no chamfer; 1: chamfer (45 degree) at max-z end;\r
-// 2: chamfer at both ends, 3: chamfer at z=0 end.\r
-// leadfac - scale of leadin chamfer (default: 1.0 = 1/2 thread).\r
-// test - true = do not render threads (just draw "blank" cylinder).\r
-// Default: false (draw threads).\r
-module metric_thread (diameter=8, pitch=1, length=1, internal=false, n_starts=1,\r
- thread_size=-1, groove=false, square=false, rectangle=0,\r
- angle=30, taper=0, leadin=0, leadfac=1.0, test=false)\r
-{\r
- // thread_size: size of thread "V" different than travel per turn (pitch).\r
- // Default: same as pitch.\r
- local_thread_size = thread_size == -1 ? pitch : thread_size;\r
- local_rectangle = rectangle ? rectangle : 1;\r
-\r
- n_segments = segments (diameter);\r
- h = (test && ! internal) ? 0 : (square || rectangle) ? local_thread_size*local_rectangle/2 : local_thread_size / (2 * tan(angle));\r
-\r
- h_fac1 = (square || rectangle) ? 0.90 : 0.625;\r
-\r
- // External thread includes additional relief.\r
- h_fac2 = (square || rectangle) ? 0.95 : 5.3/8;\r
-\r
- tapered_diameter = diameter - length*taper;\r
-\r
- difference () {\r
- union () {\r
- if (! groove) {\r
- if (! test) {\r
- metric_thread_turns (diameter, pitch, length, internal, n_starts,\r
- local_thread_size, groove, square, rectangle, angle,\r
- taper);\r
- }\r
- }\r
-\r
- difference () {\r
-\r
- // Solid center, including Dmin truncation.\r
- if (groove) {\r
- cylinder (r1=diameter/2, r2=tapered_diameter/2,\r
- h=length, $fn=n_segments);\r
- } else if (internal) {\r
- cylinder (r1=diameter/2 - h*h_fac1, r2=tapered_diameter/2 - h*h_fac1,\r
- h=length, $fn=n_segments);\r
- } else {\r
-\r
- // External thread.\r
- cylinder (r1=diameter/2 - h*h_fac2, r2=tapered_diameter/2 - h*h_fac2,\r
- h=length, $fn=n_segments);\r
- }\r
-\r
- if (groove) {\r
- if (! test) {\r
- metric_thread_turns (diameter, pitch, length, internal, n_starts,\r
- local_thread_size, groove, square, rectangle,\r
- angle, taper);\r
- }\r
- }\r
- }\r
- }\r
-\r
- // chamfer z=0 end if leadin is 2 or 3\r
- if (leadin == 2 || leadin == 3) {\r
- difference () {\r
- cylinder (r=diameter/2 + 1, h=h*h_fac1*leadfac, $fn=n_segments);\r
-\r
- cylinder (r2=diameter/2, r1=diameter/2 - h*h_fac1*leadfac, h=h*h_fac1*leadfac,\r
- $fn=n_segments);\r
- }\r
- }\r
-\r
- // chamfer z-max end if leadin is 1 or 2.\r
- if (leadin == 1 || leadin == 2) {\r
- translate ([0, 0, length + 0.05 - h*h_fac1*leadfac]) {\r
- difference () {\r
- cylinder (r=diameter/2 + 1, h=h*h_fac1*leadfac, $fn=n_segments);\r
- cylinder (r1=tapered_diameter/2, r2=tapered_diameter/2 - h*h_fac1*leadfac, h=h*h_fac1*leadfac,\r
- $fn=n_segments);\r
- }\r
- }\r
- }\r
- }\r
-}\r
-\r
-\r
-// ----------------------------------------------------------------------------\r
-// Input units in inches.\r
-// Note: units of measure in drawing are mm!\r
-module english_thread (diameter=0.25, threads_per_inch=20, length=1,\r
- internal=false, n_starts=1, thread_size=-1, groove=false,\r
- square=false, rectangle=0, angle=30, taper=0, leadin=0,\r
- leadfac=1.0, test=false)\r
-{\r
- // Convert to mm.\r
- mm_diameter = diameter*25.4;\r
- mm_pitch = (1.0/threads_per_inch)*25.4;\r
- mm_length = length*25.4;\r
-\r
- echo (str ("mm_diameter: ", mm_diameter));\r
- echo (str ("mm_pitch: ", mm_pitch));\r
- echo (str ("mm_length: ", mm_length));\r
- metric_thread (mm_diameter, mm_pitch, mm_length, internal, n_starts,\r
- thread_size, groove, square, rectangle, angle, taper, leadin,\r
- leadfac, test);\r
-}\r
-\r
-// ----------------------------------------------------------------------------\r
-module metric_thread_turns (diameter, pitch, length, internal, n_starts,\r
- thread_size, groove, square, rectangle, angle,\r
- taper)\r
-{\r
- // Number of turns needed.\r
- n_turns = floor (length/pitch);\r
-\r
- intersection () {\r
-\r
- // Start one below z = 0. Gives an extra turn at each end.\r
- for (i=[-1*n_starts : n_turns+1]) {\r
- translate ([0, 0, i*pitch]) {\r
- metric_thread_turn (diameter, pitch, internal, n_starts,\r
- thread_size, groove, square, rectangle, angle,\r
- taper, i*pitch);\r
- }\r
- }\r
-\r
- // Cut to length.\r
- translate ([0, 0, length/2]) {\r
- cube ([diameter*3, diameter*3, length], center=true);\r
- }\r
- }\r
-}\r
-\r
-\r
-// ----------------------------------------------------------------------------\r
-module metric_thread_turn (diameter, pitch, internal, n_starts, thread_size,\r
- groove, square, rectangle, angle, taper, z)\r
-{\r
- n_segments = segments (diameter);\r
- fraction_circle = 1.0/n_segments;\r
- for (i=[0 : n_segments-1]) {\r
- rotate ([0, 0, i*360*fraction_circle]) {\r
- translate ([0, 0, i*n_starts*pitch*fraction_circle]) {\r
- //current_diameter = diameter - taper*(z + i*n_starts*pitch*fraction_circle);\r
- thread_polyhedron ((diameter - taper*(z + i*n_starts*pitch*fraction_circle))/2,\r
- pitch, internal, n_starts, thread_size, groove,\r
- square, rectangle, angle);\r
- }\r
- }\r
- }\r
-}\r
-\r
-\r
-// ----------------------------------------------------------------------------\r
-module thread_polyhedron (radius, pitch, internal, n_starts, thread_size,\r
- groove, square, rectangle, angle)\r
-{\r
- n_segments = segments (radius*2);\r
- fraction_circle = 1.0/n_segments;\r
-\r
- local_rectangle = rectangle ? rectangle : 1;\r
-\r
- h = (square || rectangle) ? thread_size*local_rectangle/2 : thread_size / (2 * tan(angle));\r
- outer_r = radius + (internal ? h/20 : 0); // Adds internal relief.\r
- //echo (str ("outer_r: ", outer_r));\r
-\r
- // A little extra on square thread -- make sure overlaps cylinder.\r
- h_fac1 = (square || rectangle) ? 1.1 : 0.875;\r
- inner_r = radius - h*h_fac1; // Does NOT do Dmin_truncation - do later with\r
- // cylinder.\r
-\r
- translate_y = groove ? outer_r + inner_r : 0;\r
- reflect_x = groove ? 1 : 0;\r
-\r
- // Make these just slightly bigger (keep in proportion) so polyhedra will\r
- // overlap.\r
- x_incr_outer = (! groove ? outer_r : inner_r) * fraction_circle * 2 * PI * 1.02;\r
- x_incr_inner = (! groove ? inner_r : outer_r) * fraction_circle * 2 * PI * 1.02;\r
- z_incr = n_starts * pitch * fraction_circle * 1.005;\r
-\r
- /*\r
- (angles x0 and x3 inner are actually 60 deg)\r
-\r
- /\ (x2_inner, z2_inner) [2]\r
- / \\r
- (x3_inner, z3_inner) / \\r
- [3] \ \\r
- |\ \ (x2_outer, z2_outer) [6]\r
- | \ /\r
- | \ /|\r
- z |[7]\/ / (x1_outer, z1_outer) [5]\r
- | | | /\r
- | x | |/\r
- | / | / (x0_outer, z0_outer) [4]\r
- | / | / (behind: (x1_inner, z1_inner) [1]\r
- |/ | /\r
- y________| |/\r
- (r) / (x0_inner, z0_inner) [0]\r
-\r
- */\r
-\r
- x1_outer = outer_r * fraction_circle * 2 * PI;\r
-\r
- z0_outer = (outer_r - inner_r) * tan(angle);\r
- //echo (str ("z0_outer: ", z0_outer));\r
-\r
- //polygon ([[inner_r, 0], [outer_r, z0_outer],\r
- // [outer_r, 0.5*pitch], [inner_r, 0.5*pitch]]);\r
- z1_outer = z0_outer + z_incr;\r
-\r
- // Give internal square threads some clearance in the z direction, too.\r
- bottom = internal ? 0.235 : 0.25;\r
- top = internal ? 0.765 : 0.75;\r
-\r
- translate ([0, translate_y, 0]) {\r
- mirror ([reflect_x, 0, 0]) {\r
-\r
- if (square || rectangle) {\r
-\r
- // Rule for face ordering: look at polyhedron from outside: points must\r
- // be in clockwise order.\r
- polyhedron (\r
- points = [\r
- [-x_incr_inner/2, -inner_r, bottom*thread_size], // [0]\r
- [x_incr_inner/2, -inner_r, bottom*thread_size + z_incr], // [1]\r
- [x_incr_inner/2, -inner_r, top*thread_size + z_incr], // [2]\r
- [-x_incr_inner/2, -inner_r, top*thread_size], // [3]\r
-\r
- [-x_incr_outer/2, -outer_r, bottom*thread_size], // [4]\r
- [x_incr_outer/2, -outer_r, bottom*thread_size + z_incr], // [5]\r
- [x_incr_outer/2, -outer_r, top*thread_size + z_incr], // [6]\r
- [-x_incr_outer/2, -outer_r, top*thread_size] // [7]\r
- ],\r
-\r
- faces = [\r
- [0, 3, 7, 4], // This-side trapezoid\r
-\r
- [1, 5, 6, 2], // Back-side trapezoid\r
-\r
- [0, 1, 2, 3], // Inner rectangle\r
-\r
- [4, 7, 6, 5], // Outer rectangle\r
-\r
- // These are not planar, so do with separate triangles.\r
- [7, 2, 6], // Upper rectangle, bottom\r
- [7, 3, 2], // Upper rectangle, top\r
-\r
- [0, 5, 1], // Lower rectangle, bottom\r
- [0, 4, 5] // Lower rectangle, top\r
- ]\r
- );\r
- } else {\r
-\r
- // Rule for face ordering: look at polyhedron from outside: points must\r
- // be in clockwise order.\r
- polyhedron (\r
- points = [\r
- [-x_incr_inner/2, -inner_r, 0], // [0]\r
- [x_incr_inner/2, -inner_r, z_incr], // [1]\r
- [x_incr_inner/2, -inner_r, thread_size + z_incr], // [2]\r
- [-x_incr_inner/2, -inner_r, thread_size], // [3]\r
-\r
- [-x_incr_outer/2, -outer_r, z0_outer], // [4]\r
- [x_incr_outer/2, -outer_r, z0_outer + z_incr], // [5]\r
- [x_incr_outer/2, -outer_r, thread_size - z0_outer + z_incr], // [6]\r
- [-x_incr_outer/2, -outer_r, thread_size - z0_outer] // [7]\r
- ],\r
-\r
- faces = [\r
- [0, 3, 7, 4], // This-side trapezoid\r
-\r
- [1, 5, 6, 2], // Back-side trapezoid\r
-\r
- [0, 1, 2, 3], // Inner rectangle\r
-\r
- [4, 7, 6, 5], // Outer rectangle\r
-\r
- // These are not planar, so do with separate triangles.\r
- [7, 2, 6], // Upper rectangle, bottom\r
- [7, 3, 2], // Upper rectangle, top\r
-\r
- [0, 5, 1], // Lower rectangle, bottom\r
- [0, 4, 5] // Lower rectangle, top\r
- ]\r
- );\r
- }\r
- }\r
- }\r
-}\r
-\r
-\r
~ianmdlvl / reprap-play.git / blobdiff