The 37° is the angle of the taper seal in aircraft fittings. Automotive uses
45°. So when you work on an aircraft, that is what you expect. Mixing the
two could be a big problem. With that said, My Factory built Bellanca has
two different style fittings as it was built with war surplus Air Corp
fittings. Since they are no longer available, some of the later repairs and
alterations use the current style fittings. They are both 37° but the nut
threads are different. AC fittings were gray, Current are blue.


--
Cy Galley - Chair, Emergency Aircraft Repair
Safety Programs Editor - TC
EAA Sport Pilot


"Ernest Christley" wrote in message
. com...
The most recent Sport Aviation has an article on make up hoses. The
author states that 'you must use 37 degree fittings' and as is typical,
gives no reason why. Is there a reason for this that involves the laws
of nature, vs the "laws of the FAA"?

--
http://www.ernest.isa-geek.org/
"Ignorance is mankinds normal state,
alleviated by information and experience."
Veeduber