$fn=20;
h=3.5; // height
w=5; // width
int = w/4; // interhal hole
angle=21.2; // angle in bewween side holes

difference() {
	cylinder(h,r=w);
	cylinder(2.01*h, r=int, center=true);

    translate([0.5 * w,0,h/2])
        rotate([-90,0,0])
        cylinder(d=1,h=w+1);

	for (i = [1:20:1])
	{
        rotate([-90, i + angle, 0])
            translate([0, i + angle, 0])
            cylinder(d=1,h=w+1);
	}
}