// resolution
$fn = 50;

// Parameters
inner_radius = 120;
thickness = 30;
outer_radius = inner_radius + thickness;
height = 18;
padding = 0;
magnet_width=6.35;
magnet_height=3.17;

module ring(inner_radius, thickness, height) {
    difference() {
        // This piece will be created:
        cylinder(r=inner_radius + thickness, h=height, center=false);
     
        // Everything else listed will be taken away:
        cylinder(r=inner_radius, h=height, center=false);       
    }
}

difference() {
    
    ring(inner_radius,thickness,height);

    translate([0,0,height-5]) {
       ring(inner_radius+20,10,5);
    }
        
    translate([0,0,0]) {
       ring(inner_radius,20,5);
    }
    
    translate([inner_radius+10,0,height-magnet_height]) {
        cylinder(r=magnet_width, h=magnet_height, center=false);
    }
    
    rotate([0,0,120]) {
        translate([inner_radius+10,0,height-magnet_height]) {
            cylinder(r=magnet_width, h=magnet_height, center=false);
        }
    }
    
    rotate([0,0,240]) {
        translate([inner_radius+10,0,height-magnet_height]) {
            cylinder(r=magnet_width, h=magnet_height, center=false);
        }
    }
    
    //bottom holes
    rotate([0,0,60]) {
        translate([inner_radius+10,0,5]) {
            cylinder(r=magnet_width, h=magnet_height, center=false);
        }
    }
    
    rotate([0,0,180]) {
        translate([inner_radius+10,0,5]) {
            cylinder(r=magnet_width, h=magnet_height, center=false);
        }
    }
    
    rotate([0,0,300]) {
        translate([inner_radius+10,0,5]) {
            cylinder(r=magnet_width, h=magnet_height, center=false);
        }
    }
}