I've been asked for T-Slot nuts for the Sherline machines so I had some made. As you can see from the pictures their real T-Slot Nuts. Not like the cheap version sold from Sherline. They do have a 10-32 thread.
One question I've gotten is about a thread break. Yes there is a type of thread break. The last of the thread is scored so the screw can't exit the bottom of the nut. I tried to get pictures of it but it's so small it doesn't show up in pictures.