Alright... I have been splitting several schedule 40 1in valves during the set up of the plumbing for my new tank. I can't figure out why except to think now that the schedule 80 1in male/slip adapters are the culprit. I have been putting 5 turns of teflon tape on the threads and tightening them just beyond hand tight. There is still a couple of threads showing on the adapters. A couple of the valves split a day after install while the pump was running.