Earlier, Lou wrote:
My plans call for the use of 2024 1.5mm to use in the forming of
brackets that will hold the bellcranks....

So can anyone give me good reasons why I shouldn't use
this in place of the 2024?

I've made bellcrank leaves and mounts out of .063" 6061-T6 where I was
sure that the applied stresses fell within the material properties.
For forming operations, one good reference is the table of minimum
bend radii reproduced in the Aircraft Spruce catalog:

http://www.aircraftspruce.com/catalo...s/aluminfo.php

There's nothing magic about 2024-T3. It is stronger than 6061-T6, and
a bit more expensive, and for many or most applications the extra
strength is worth the extra money. However, it has the same stiffness
as 6061, so for stiffness-bound applications there's not much point in
using 2024. Control push-pull tubes is a good example of this - one of
my favorite Stan Hall articles points out that push-pull tubes are
pretty universally stiffness-bound by buckling properties.

Anyhow, if you've done analysis on the mechanism and surrounding
structure, if you're confident you've correctly estimated the maximum
hinge moment, and also figured in reasonable (JAR 22 or Part 23 or
other appropriate) maximum input forces, and accounted for appropriate
safety factors, if you've accounted for 6061-T6's lower ultimate and
yield stesses, and found this to be a valid substitution, I say go for
it.

If you haven't done that analysis and are just guessing, sticking with
what the plans call for will save you some sleepless nights spent
second-guessing yourself.

As for another poster who says that 6061-T6 is too brittle, do you
have a cite for that very general assertion? How does that reconcile
with the fact that Zenith makes entire airplanes out of the stuff?

Thanks, Bob K.
http://www.hpaircraft.com/hp-24