When using 4-40 rods at the servo, I silver-solder brass 4-40 rod ends to the rod and I use a 4-40 Sullivan clevis with the little keeper that comes with the clevis and a 4-40 plain nut to lock against the clevis (nut keeps the clevis from moving on the threaads and possibly wearing the threads). The 4-40 rod ends are made by Dubro, Great panes and Sullivan. They have a female end that the 4-40 plain rod slips into, then silver-solder. Before soldering, use coarse sandpaper to rough-up the the rod for better solder adhesion. I think the zbends wear the servo arm 'cause the vertical part of the zbend is not a consistent diameter due to the tool maybe leaving marks.