For what it's worth, I use a 50lb test braided line (spiderwire) secured under the head with a round turn and two half hitches. Hasn't failed me yet, even with axles glued at the relief hole. Stay away from monofilament. I pull in the direction of the sofa so if the axle comes flying out, at least it doesn't go far and has a soft landing! I also make sure my wife's not in the room to laugh at me.