// #######################################################
// ###################### Mechanics ######################
// #######################################################

rail_mount_wall = 5;
rail_mount_len = 10;
rail_mount_block = 22;
rail_dia = 8;
rail_y_off_1 = 10;
cutout_width = 0.5;

rail_mount_height = rail_y_off_1 + 6;
rail_y_off = rail_dia / 2 + rail_y_off_1;

draw_rail_mount = false;
    
// #######################################################

if (draw_rail_mount) rail_mount(30, 20);

module rail_mount(slot, rail_mount_len = rail_mount_len) {
    $fn = 20;
    
    echo(rail_mount_len=rail_mount_len);
    
    difference() {
        union() {
            // main body
            cube([rail_mount_wall, rail_mount_len, 2 * slot]);
            
            // rail clamp
            translate([rail_mount_wall, 0, ((2 * slot) - rail_mount_block ) / 2])
                cube([rail_mount_height, rail_mount_len, rail_mount_block]);
        }

        // M4 slot mounting holes
        translate([-1, rail_mount_len / 2, slot / 2])
            rotate([0, 90, 0])
            cylinder(d = 4.2, h = rail_mount_wall + 2);
        translate([-1, rail_mount_len / 2, slot * 3 / 2])
            rotate([0, 90, 0])
            cylinder(d = 4.2, h = rail_mount_wall + 2);
        
        translate([rail_dia / 2 + rail_y_off_1, -1, slot])
            rotate([-90, 0, 0])
            cylinder(d = rail_dia + 0.1, h = rail_mount_len + 2);
        
        // clamping cutout
        translate([rail_y_off_1 + (rail_dia - cutout_width) / 2, -1, ((2 * slot) - (rail_mount_block + 2)) / 2])
            cube([cutout_width, rail_mount_len + 2, rail_mount_block + 2]);
        
        translate([-1, rail_mount_len / 2, slot + rail_mount_block / 3])
        rotate([0, 90, 0]) {
            cylinder(d = 3.2, h = rail_mount_height + rail_mount_wall + 2);
            
            cylinder(d = 6.1, h = 3.8, $fn = 6);
            
            translate([0, 0, rail_mount_height + rail_mount_wall -2.5])
                cylinder(d = 6.1, h = 3.8);
        }
        
        translate([-1, rail_mount_len / 2, slot - rail_mount_block / 3])
        rotate([0, 90, 0]) {
            cylinder(d = 3.2, h = rail_mount_height + rail_mount_wall + 2);
            
            cylinder(d = 6.1, h = 3.8, $fn = 6);
            
            translate([0, 0, rail_mount_height + rail_mount_wall -2.5])
                cylinder(d = 6.1, h = 3.8);
        }
        
        translate([-10, -10, -22])
            cube([30, rail_mount_len + 20, 30]);
        
        translate([-10, -10, 2 * slot - 8])
            cube([30, rail_mount_len + 20, 30]);
    }
}