I use a large spring from an old type writer. You can get springs at the hardware store tool. Easy on and off, they don't break or let go, and I don't have to worry about it. I did use different J bolts. I also added some ply for them to screw into so they would not come out under any condition. I throw it around pretty hard and didn't want to have one come off. Been using springs for years in my big gliders. They have always worked well.