I've tried Tornado men on 5/8 rod... too tight. Returned men before I broke one trying to install. Tornado rods are 0.620, most would think that .005" wouldn't make that much of a difference but I had clamps pulling the guys and lube on the rod and I felt like a break was imminent. Also made a sleeve to go over the rod so I could use a mallet and pound them on... not worth it. Fireball guys however are 5/8" but not as inexpensive or as available.