Folks, I am working on two related videos about the above title. I thought I would give everyone in this forum a heads up about what’s next while I wait for my sample prints to complete.

The first highlights a number of OpenSCAD models that you can use to produce practical prints of brackets, hinges, chains, nuts, and bolts. The goal of the video is to introduce a number of practical uses for 3d printers.

In the video, I demonstrate a new OpenSCAD shelf bracket scripts I wrote for the video. Then in a follow-up video, I will walk folks through the code in the shelf bracket script and introduce the use of trigonometry in OpenSCAD. Here is an early version of the code I will explain in the video.

```
/*
* Copyright (c)..: 2020 Cogitations, LLC
*
* Author: Irv Shapiro for the DrVAX youtube channel
* Creation Date..: 03/2021
* Description....: Customizable Shelf Bracket
*
* 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 2 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.
*/
/* Excellent resource for OpenSCAD syntax */
/* https://www.openscad.org/cheatsheet/ */
/* [Shelf Bracket Dimensions] */
base = 150.0;
side = 75.0;
width = 25.0;
thickness = 5.0;
screw_hole = 4.5;
/* [Hidden] */
$fn = 25; // number of sides in a circle
depth = thickness;
hole_1 = 40;
hole_2 = base - 40;
hole_3 = 20;
hole_4 = side - 20;
angle_attachment = side /2;
/* Horizontal Leg, with 2 screw holes */
difference(){
difference() {
/* horizontal leg */
cube([base,width,depth], center = false);
/* screw hole 1 */
translate([hole_1,width/2,-2])
cylinder( h=depth+3, d=screw_hole);
}
/* screw hole 2 */
translate([hole_2,width/2,-2])
cylinder( h=depth+3, d=screw_hole);
}
/* Vertical Leg, with 2 screw holes */
difference(){
difference() {
/* vertical leg */
cube([depth,width,side], center = false);
/* screw hole 1 */
translate([-2,width/2,hole_3])
rotate([0,90,0])
cylinder( h=depth+3, d=screw_hole);
}
/* screw hole 2 */
translate([-2,width/2,hole_4])
rotate([0,90,0])
cylinder( h=depth+3, d=screw_hole);
}
/************************************************** *******************
Add the cross beam at an angle
Calculate the length of the cross beam using a^2 + b^2 = c^2
Sin (x) = Opposite / Adjacent
angle of cross beam = inverse sin(Opposite / Adjacent)
************************************************** *******************/
a = side/2;
b = base/2;
c = sqrt((a^2)+(b^2));
angle = asin(a/c);
translate([0,0,angle_attachment])
rotate([0,angle,0])
cube([c,width,depth], center = false);
/* end of script */
```

Enjoy.