> Making such a flare is easy: if you are in possession of a standard 45
> degree double flaring tool, the bubble flare is what results after the
> first
> half of the operation. Simply stop there, and you have the bubble flare
> which will seat nicely at the bottom of the hole. If you continue,
> inverting
> the form tool and finishing the job, you *then* have the more familiar
> double flare used by Girling and the US automotive industry.
>
> REFERENCE:
> http://www.dimebank.com/BrakePlumbing.html
> --
> Shawn Feller
> Ohio
> www.carboncow.com
>

Shawn,
  You appear to have stated this personally, by not using quotation marks
around the plaigarized text from another author.  The 'reference' you claim
is not correct, either.  Again a case of the internet causing people to take
as true something that is put in writing by someone else.   It is a
double-edged sword here, and all infor posted should be cross-checked from
several different authors to be able to decide what's actually true and
correct.
  The part about stopping at a halfway-formed double flare as sufficient for
an ISO bubble flare is an over-simplification of the truth, and is NOT
correct.  The resulting shapes after forming each are distinctly different,
and this is why they sell different tools for each use; not because they
assume all mechanics are too stupid to realize that the one tool would do it
all.
  It may work good enough for that author, but not good enough for me to
trust my whole family's lives on.  The poorly-shaped half-formed double
flare won't seal up correctly.  The fitting will be attempting to force the
tubing into the correct shape when tightening it down, and will not do a
good job of it.  It's a hack way to work, attempting to out-think the
engineers, and I simply don't take such risks just to save a few bucks.  The
correct tool will do them all, and apparently isn't even that expensive
nowadays.

Mike B.