3 * Replacement tensioner for the Sparrows disc-detainer picking tool
5 * (c) 2023 Mark Wooding
8 /*----- Licensing notice --------------------------------------------------*
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.
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.
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/>.
24 /*----- Configuration -----------------------------------------------------*/
26 /* Overall scaling. */
29 /* Curvature quality. */
33 /* A `large enough' length; effectively infinite. */
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 */
47 /*----- The main object ---------------------------------------------------*/
51 /* Start with a cylinder. */
53 cylinder(h = STOCK_LENGTH, r = STOCK_DIAM/2);
55 /* And now we cut things away. */
58 /* First, put the flat sides so that the tensioning arms can grip it. */
59 for (theta = [0 : 90 : 270])
61 translate([0, -BIG/2, SQUARE_SIDE/2])
62 cube([SQUARE_LENGTH, BIG, BIG]);
64 /* Drill a hole all the way through for the picking tip. */
66 cylinder(h = BIG, r = DRILL_DIAM/2);
68 /* Drill a hole in the end to form the gap between the prongs. */
69 translate([STOCK_LENGTH - PRONG_DEPTH, 0, 0])
71 cylinder(h = BIG, r = PRONG_DIAM/2);
73 /* Finally, shave off top and bottom to form the prongs themselves. */
74 for (theta = [0 : 180 : 180])
76 translate([STOCK_LENGTH - PRONG_LENGTH,
78 (STOCK_DIAM - PRONG_HEIGHT)/2])