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