Ok, I think I've figured out how to do this now.
From banks@keysnet.net
I'm searching for a set of hatch rings. I've seen them used on large
military submarines. They close and then have a small twist to them, about
4 or 5 degrees. This locks them together. The rings would come as a set
having a male and a female and they compress the "O" ring using the
principle of an incline plane. I'm not sure of their correct name but I
think it's called a "rotating interrupted screw". These rings I'm looking
for my not be associated with a submarine because they're also used in the
pressure vessel industry but would fit my purpose. If any of you live or
pass by a location that builds or uses pressure vessels you might see a set
of these sitting over in a field or beside a ware house, we just never know,
do we. One place that I'm sure most of you have seen these rings is on a
pressure cooker that Mom may have used. The perfect size I'm looking for
would be between 42 and 38 inches but we all know that never happens. I
would also certainly consider purchasing a set of new rings if any one knows
of a company that machines them. I've spent hours searching pressure vessel
web sites but have not located any information regarding theses rings. I'm
a very new member and I'm not sure if this is the proper posting method, but
I'll quickly find out. I will close by saying thank you to every one that
reads this and that I have looked at many of the subs pictured on the site.
Many of them are very impressive and a nice job on the site too.
Best regards & keep on welding. David
J. Banks