If you have a cast BB shell that looks like it matches the Nervex lug, then you may have a Hayden "Firefly" BB shell. I've got some, haven't used any yet. Check to see if the width of the shell is 65mm. If it is then it's probably a Hayden. You'll have to widen the shell to 68mm if you want to use it.
I think genuine Nervex BB shells are pressed steel; have the name Nervex on it, and have the angles listed on the bottom.
> Framebuilders on the list, is this true? I've got two Nervex Legere lug
> sets that came with shells, one is going to be an SPX tubed touring frame
> for a friend of mine. Are there real reasons that I should not use the
> shell? It's pretty stout looking, kind of roughly cast but there's plenty
> of metal where metal needs to be removed. I've also seen lots of high
> quality frames that have lasted many years with them. Is what Phil is
> saying for real?
> David Feldman
> >From: Philcycles@aol.com
> >To: email@example.com
> >Cc: firstname.lastname@example.org
> >Subject: Re: [Classicrendezvous] nervex professional question.
> >Date: Mon, Nov 13, 2000, 4:03 PM
> >In a message dated 11/13/0 10:34:56 PM, email@example.com writes:
> >> I've also got a custom frame of my own and it
> >>doesn't use this bottom bracket shell either; instead it has what looks
> >>to be a modified Henry James bb shell. Why don't builders use that
> >The Nervex shell, while pretty, has the structural strength of paper mache. I
> >built a frame with one many years ago and I'll never do that again. Very
> >Phil Brown