On Wednesday, May 22, 2019 at 8:03:25 PM UTC-5, Scott Williams wrote:
On Saturday, January 20, 2018 at 6:49:59 PM UTC-6, John DeRosa OHM Ω http://aviation.derosaweb.net wrote:
I am looking for an oxygen bottle to fit my ASW-27B. I cannot find a US bottle that fits the factory sleeve located at my right hip. I have determined that the circumference cannot be larger than 13-5/16" or 337mm.

Contact me via email at jhderosa at yahoo. Thanks.

The Luxfer m15A here, 4 inches diameter, 15 inches tall, not counting the valve
https://legacy.life-assist.com/Produ...-Cylinders/929
a fellow club member has an asg-29 and one of these luxfer M15A-5 fits, and is capable of 3000 psi. if you can find a supplier who can fill to that pressure.

Odd how often this same query comes up about O2 bottles for ASW-27. And this one started (by me) in January of 2018! Anyway here is what I have said previously about my (successful) search ...

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After I bought my ASW-27 I had to do some major league searching to find a bottle that would fit my ship. Took more than a year to find one. Luckily a friend that owns an ASW-24 lent me his bottle for a western trip. Thanks, Geoff.

Bottom line is that the critical dimension is the diameter (no duh) which, to me, is rather difficult to measure accurately unless you have a particularly large caliper hanging around. Accurate measuring is especially dicey when you are asking a seller of unknown resources/capabilities to measure their bottle.

So, using my friend's bottle, I came up with the following CIRCUMFERENCE which is much easier to measure accurately. This I could then give to prospective bottle providers for them to measure what they have in stock before purchasing.

Here is what I came up with;

Circumference = 13-5/32" = 13.15625" = 334.2mm
QED Diameter = 4-3/16" = 4.1875 = 106.4mm

The question is then how to have someone else easily and accurately measure circumference? A carpenter's steel measuring tape will NOT wrap around a cylinder. A tailor's cloth tape is great but is much less likely to be found in the average pilot's tool box.

The easiest way I found is to have the seller wrap a (long narrow) piece of paper around the bottle, mark where the edges meet, lay the paper out flat on a table, and then accurately measure between the marks with a simple flat ruler - preferably in metric because +/- 1mm is ok but counting 16ths of a inch is more prone to error (ask me how I know).

Be prepared to suffer multiple disappointments in your search.

My overblown $0.02,
John OHM Ω