// polygon quality
$fn=60; //[20:10:200]

// for the ball and the socket
radius=5; //[1:.5:25]

// how deeply the ball snaps into the socket
inset=1.5; //[0:.1:25]

// how long it be
stem_length=1; //[1:.5:100]

// how thick the stem should be
stem_radius=radius * .5; //[.5:.5:24]

// added to the radius of the socket to make wiggle room, if desired
play=0; //[0:.1:1]

// without some padding the socket cuts too closely to the edge of the cylinder it is in
padding=.1; //[0.1:.1:1]

union() {
    // socket
    difference() {
        cylinder(radius + inset + play, radius + padding + play, radius + padding + play);
        translate([0, 0, inset]) {
            sphere(radius + play);
        }
     }
     
     // stem
     translate([0, 0, radius + inset + play]) {
        cylinder(stem_length, stem_radius, stem_radius);
     }
     
     // ball
     translate([0, 0, radius * 2 - 1 + stem_length + inset]) {
        sphere(radius);
     }
 }