[Spridgets] bugeye fuel tank fitting

[Walt Swift]

Help.  I have a new fuel tank from Moss and an old, rusted, leaky one pulled
from a tub.  The male and female fittings in each tank appear to be the same -
1/4" BSPP thread.  The male fitting from the old tub is seriously buggered and
attached to a 1/4" copper tube.  As I recall it fit tightly in the original
tank.  I sourced a replacement male fitting and olive (ferrule) that
dimensionally seem to match the original.  But the new male fitting doesn't
seal in the new female fitting.  On further examination, the old male fitting
doesn't seal in the old tank (PO made the seal with RTV?)

HAs anyone run thru
the permutations of getting a good match between the tank and a BSPP male
fitting?  I sourced mine from British Metrics (item METRO-001).  I think the
lousy seal is because of a slight mismatch in length - i.e.,
tolerancing/manufacturing.  My measurements indicate that if the olive were
another 0.020" longer or the male threaded fitting was another 0.020" in
length, I'd get a good seal - i.t., the male fitting face wouldn't bottom
against the female fitting face before the olive made the compression fit.
Pic of both parts attached.

Any help appreciated ...

Walt

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