Rod ends are from Junfac. I believe i just used 10-32 threaded rod for the links. Made it nice for mocked up so if they were the wrong length (which they were) I could cut down the rod or make a new rod cheap. Then when they were right I sleeved them with some Delring. I think the delrin i found was from
www.mcmaster.com and was 1/2" OD and around 3/16" or 1/4" ID.
They're been punished pretty good and I've never broke one yet!