When did the first 3/4” thread come out on 72’s?

[Eric Sedletzky]

Just curious, but who knows what year the first 3/4” straight thread w/ O-ring steel 72 came out?
I had a 1959 and 1960 tanks but they were 1/2” taper.
The oldest 72 in my gang I currently have is a 1967 and it’s 3/4”.
Anybody?

 

[runsongas]

1960 US Divers was the oldest catalog I could find with a 3/4 valve option

 

[Sam Miller III]

1960 US Divers Catalog Page 6

 

[Luis H]

Yeah, US Divers 1960 catalog seems to be the earliest I could also find.

Dacor shows a transition in the 1963 catalog and Healthways shows both types of valve threads in the 1966 catalog. It is interesting that the front cover picture of the 1965 Healthways catalog shows a cylinder with a 3/4" valve, but inside the catalog they are only advertising the 1/2" tapered threaded valve.

The earliest Sportways catalog I have 1969, has the 1/2" with O-ring straight pipe thread valves. Sportways pushed that smaller thread O-ring valve until around 1967, but I am very glad they lost their competition in market acceptance. Heck, I wish we had a slightly bigger neck opening.

 

[captain]

I have a USD tank from Mar. 58. It has a 1/2" valve but the tank has the larger neck as used with the 3/4" valve.

 

[Luis H]

I have a USD tank from Mar. 58. It has a 1/2" valve but the tank has the larger neck as used with the 3/4" valve.

Does it have an adapter from tapered 1/2" to the straight 3/4" pipe thread (with O-ring) or is it a tapered 3/4" pipe thread?


Yeah, the catalogs were never a precise representation of what was always available. Sometimes they advertised stuff ahead of actual release and sometime it was the opposite, items were released that did not make it to the printed catalog.

 

[Eric Sedletzky]

I like 3/4” because I can get cleaning tools inside the tank easier, and it’s less of a pain in the ass to do a VIP each year.
I had several 1/2” tanks which were fine, extra tanks are always good, but sold them all off because it’s difficult to whip them.

How about lined tanks, does anybody know what year span they were lining the inside of tanks with epoxy? Then there was also a vinyl outer coating I remember. I got one or those once and gave it away because I didn’t want to deal with it.

 

[captain]

No adapter, it is threaded 1/2" NPT

 

[Luis H]

Thanks

I misunderstood.

 

[Sam Miller III]

@captain
@Luiis H

@Eric S

K MAG YO YO