Bolt-style head would be great! MarkSheriffDiver wrote:Mark,
I have a set of twin Sportsways 72's at home. I'll look later when I get home. I'll see what I have laying around then. Do you want the burst discs like original with a screw driver head or a bolt style head??
Ok, figure this one out. I took the 3/8 burst disc out if your single SW valve and it fits in one of my double manifold holes but not the other. Neither if my new replacement burst discs fit in either manifold hole but easily fit into your single valve. The threads on the manifold look fine but maybe I should run a 3/8 tap through each to make sure? What thread size tap should I use (if that is the correct term - don't know much about taps.) Anyone? Thanks, MarkSheriffDiver wrote:Just looking at your picture Mark and then looking at my twin manifold that hole size looks the same as mine.
I tend to think the threads may just be damaged, and maybe not a mis-match on size. I have not seen any plugs with straight threads smaller than the standard 3/8x24, but that's not to say they couldn't exist.ScubaLawyer wrote:Thanks for the reply Eben. The simplest approach is usually the best approach so I'll be off to the hardware store (again). My research has shown the new-style burst discs are 3/8-24UNF but someone please correct me if I'm wrong (or advise if i am right). I had a bitch of a time getting the old-style recessed plugs out so I could have easily buggered up the threads on the manifold to some degree. I've put too much time, money and sweat into this project to give up now. Maybe a hand tap will reinjuvinate the threads. Mark
Thanks for the offer Ron. I do have two brand new discs I got from a guy who at least claims to be reputable.SheriffDiver wrote:Mark,
I do have plenty of burst plugs unless you want to use a brand new one. Just throwing that option out there.
Mark, there is a big difference. The "3/8" is obviously the OD measurement, and just as important is the "-24", which indicates the number of threads per inch (tpi), also referred to as "pitch". All the 3/8 plugs in my limited experience are -24's... which is the fine thread, "UNF". The "UNC" stands for Unified Coarse, which is 16 tpi in the 3/8" diameter thread system. Any decent hardware store should carry both types.ScubaLawyer wrote:Ok you machinist types out there. I started looking for a bottoming tap to clear the threads on my SW elbow for the new burst disk.
I have confirmed it takes a 3/8-24 and have found many taps that size. However, it looks like some taps are UNC (course) and some are UNF (fine) both in the 3/8-24 size. Being the perfectionist I am, I'd like to use the correct tap. Here is my question: Can anyone point me to a source that will tell me if 3000psi 3/8-24 burst disk threads are UNC or UNF? maybe it doesn't make a difference? I've been researching taps until I'm blue in the butt and I figure someone here might know the answer. Thanks. Mark
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