-MIKE- wrote:
J. Clarke wrote:
-MIKE- wrote:
fftt wrote:
On Oct 10, 4:54 pm, -MIKE- wrote:
depends on the loading conditions & assembly
an ultimate number or an allowable (like a working load) number?
allowable in timber like ~100lbs
ultimate load in timber, probably 400lbs
ultimate load in a test machine...depending on the steel
condition / alloy; maybe 800+ lbs
cheers
Bob
I'm not talking about working loads or allowable anything... I
never was.

I'm talking about the weight requite to shear (tear off like being
cut, or whatever the proper scientific terminology is) a 16d nail.

Is that what that 800 number is?
Can you point me to any video.pics on the web that show the
machine/test.


Are you asking about the nail ...all by itself, no timber?
Mounted in steel test machine by some sort of fixturing?

A 16d nail has about .02 sq in cross section (as per another
poster's calc) ....so pick your nail material ultimate shear
stress & mutlitply by .02

But the shear strength of a 16d nail isolated by itself in a test
machine is pretty meaningless since a 16d nail will never be used
in that fashion unless you plan to use it as a shear pin in a lawn
mower.

cheers
Bob

Yes, the test situation, mounted in a testing machine.
There are a lot of testing situations that never happen in the real
world, but they still do the tests. :-)

If you're testing shear strength then you need to make up a fixture
that fits the nail, with a nail-sized hole in it. Seems like a
strange thing to do when a nail would not normally be used that way.
Do you recall the circumstances under which the test was conducted?


I'm not trying to justify my number, despite what douche bag Bob says
to try to make himself feel superior in some way.

I honestly want to know what the real number is. Since we had some
engineers come in here, saying they've conducted those types of tests,
I've been trying to ask them.

Have you honestly never seen those tests they do at labs
(Underwriters' Labs might be one example) where they take a material
way beyond its limits to see when it crack, shears, pulls apart,
shatters, or whatever?

They don't "take it way beyond its limits", they determine what its limits
are.

And I've not just seen such tests, I've planned and monitored them and
analyzed the results. Never had occasion to do one on a nail in a fixture
intended to determine its shear strength though. I'ts not something that I
can imagine anybody wanting to do unless they were perhaps quality control
people in a nail factory or lawyers trying to prove that a batch of nails
was defective. In most engineering you don't care how strong the _fastener_
is, you care how strong the _joint_ is and to test that you make up sample
joints and test them.

Apparently, Bob thinks I'm full of it for suggesting this happens.

No, for arguing about things like the definition of "shear".