Another Rivet Question

What are the "soft" rivets used for. In every instance on my project,
hard rivets were called for.
Just wondering.
Clark

What do you mean by soft and hard ??

I assume we are talking solids:

There are many different types of MS20470/426 rivets:

Alloy Comments
A 1100 Soft low strength alloy. Plain head. 10000 psi
shear strength.

B 5056 1/4 Hard (Low strength) - used in Magnesium as they
are corrosion resistant in combination with Magnesium. Raised cross on head.
27000 psi shear strength.

D 2017-T4 Must be heat treated prior to use and used within 15
minutes or stored in ice. Raised nipple on head. High strength applications.
34000 psi shear strength.

DD 2024-T4 Like DD except must be used within 3-5 minutes. Two
raised bars on head. High strength applications. 41000 psi shear strength.

AD 2117-T4 The standard rivet. Supplied in the heat treated form.
Driven as is. Dimple on head. Moderate strength rivet. 30000 psi shear
strength.

M Monel Two dots on head. 49000 psi shear strength.

See AC43.13-1A for a listing of many more types of rivets. See MIL-HDBK-5
and USAF T.O. 1-1A-8 Aircraft Structural Hardware for more detailed
information.

AD's are used for the vast majority of aircraft riveting. D's and DD's are
occasionally found in structures in hight strength areas but I cannot recall
having seen these in a light aircraft. I have only seen them in larger
aircraft and helicopters.

A are not that common. They are not used in primary structure (at least I
have never seen them used in this type of structure). Typically used in
secondary structure. They are easier to drive than AD's because they are
softer.

A monel rivet would be used where galivanic corrosion is a problem (i.e for
riveting nickel steel alloys) or where high strength is required. Whilst
some homebuilts (T-18 for example) do use Monel pops in aluminium this would
not be good practise because Monel and aluminium are widely separated on the
galvanic table. However you can get away with this because the anodic
material (aluminium) is present in much larger quantities than the monel.

For a homebuilt limit yourself to AD's and A's.


"c hinds" wrote in message
om...
What are the "soft" rivets used for. In every instance on my project,
hard rivets were called for.
Just wondering.
Clark

What are the "soft" rivets used for. In every instance on my project,
hard rivets were called for.
Just wondering.
Clark

We used soft rivets to attach the piano hinge to my fiberglass cowling
(upper & lower).

Rich S.

On 22 Oct 2004 19:59:35 -0700, (c hinds) wrote:

What are the "soft" rivets used for. In every instance on my project,
hard rivets were called for.
Just wondering.
Clark

A couple examples that I am aware of, you can use them to assemble
fuel tanks and once the seams are welded up you then weld over the
rivets to seal them up, which is possible because the soft rivets are
weldable 1100 alloy and the hard rivets are not weldable. I built a
pair of fuel tanks this way and it worked but next time I am going to
just put sheet metal screws in the holes and once the tank is welded
together pull the screws and weld up the holes. For whatever reason,
all but one of the leaks I found and had to re weld in my tanks were
at the rivet locations.

The other application which I am aware of pertains to the aileron
balance weights in some Cessna aircraft. A hard AD rivet shouldn't be
used because it is hard enough that as it is driven, the expansion of
the rivet will just deform (and expand) the lead balance weight.
Originally a different rivet that I believe was alloyed with magnesium
was used, but this lead to dissimilar metal corrosion so the current
method involves using a slightly bigger "A" soft rivet instead. It
has to be bigger to be strong enough, and because it is soft it won't
deform the weights when driven.

If you are going to have "A" rivets around for obvious reasons you
need to make absolutely certain that none of them migrate into your
"AD" rivet stocks, because they are much weaker.


================================================== ==
Del Rawlins--
Unofficial Bearhawk FAQ website:
http://www.rawlinsbrothers.org/bhfaq/
Remove _kills_spammers_ to reply

"c hinds" wrote in message
om...
What are the "soft" rivets used for. In every instance on my project,
hard rivets were called for.
Just wondering.
Clark

I haven't looked at AC 43-13 lately but recall that A rivets have been used
in some structural applications. Whether legally or not, don't know. I
have seen them used on trailing edges of aluminum wings and control surfaces
where driving them is done with a squeezer rather than a gun in order to
keep the trailing edge arrow-straight. In 1/8's they are much easier to
squeeze than AD rivets, which you'll over-exert yourself squeezing if you
don't watch it or are a weenie like Della. You will notice that even on new
Cessnas, like 182's for instance, the horizontal trailing edges of the flaps
are wavy, not straight. Get behind one and sight down the wing's trailing
edge from inboard to outboard and you'll see what I'm talking about.

Soft rivets are used to rivet the aluminum trailing edge on the wooden ribs
of Bellanca Flaps and Ailerons.


" jls" wrote in message
. ..

"c hinds" wrote in message
om...
What are the "soft" rivets used for. In every instance on my project,
hard rivets were called for.
Just wondering.
Clark

I haven't looked at AC 43-13 lately but recall that A rivets have been
used
in some structural applications. Whether legally or not, don't know. I
have seen them used on trailing edges of aluminum wings and control
surfaces
where driving them is done with a squeezer rather than a gun in order to
keep the trailing edge arrow-straight. In 1/8's they are much easier to
squeeze than AD rivets, which you'll over-exert yourself squeezing if you
don't watch it or are a weenie like Della. You will notice that even on
new
Cessnas, like 182's for instance, the horizontal trailing edges of the
flaps
are wavy, not straight. Get behind one and sight down the wing's
trailing
edge from inboard to outboard and you'll see what I'm talking about.

" jls" wrote in message ...
"c hinds" wrote in message
om...
What are the "soft" rivets used for. In every instance on my project,
hard rivets were called for.
Just wondering.
Clark

I haven't looked at AC 43-13 lately but recall that A rivets have been used
in some structural applications. Whether legally or not, don't know. I
have seen them used on trailing edges of aluminum wings and control surfaces
where driving them is done with a squeezer rather than a gun in order to
keep the trailing edge arrow-straight. In 1/8's they are much easier to
squeeze than AD rivets, which you'll over-exert yourself squeezing if you
don't watch it or are a weenie like Della. You will notice that even on new
Cessnas, like 182's for instance, the horizontal trailing edges of the flaps
are wavy, not straight. Get behind one and sight down the wing's trailing
edge from inboard to outboard and you'll see what I'm talking about.



I think the RV-10 uses a double countersunk rivet on their control
surfaces trailing edges. If this is correct, anybody know if they're
using hard or soft rivets here?

Neal