degrees of screw stainless steel

"Jeff Liebermann" wrote in message
...
On Sun, 11 Jun 2017 20:44:11 +0100, "Ian Field"
wrote:



"Jeff Liebermann" wrote in message
. ..
On Fri, 9 Jun 2017 18:02:30 -0500, DougC
wrote:
In the US, normal stainless bolts are mostly 304 and
extra-corrosion-resistant (marine-grade) ones are 316:
https://en.wikipedia.org/wiki/Stainless_steel

A little more on stainless:

A2 is the same as 304.
A4 is the same as 316 and contains molybdenum and more nickel and
nitrogen making it stronger and more resistant to corrosion.

You can easily tell the difference. A2 is slightly magnetic, while A4
is non-magnetic:
https://www.youtube.com/watch?v=mbbXvvpoLCo

TBH: I don't bother asking what grade when I buy SS fasteners - pretty
much
any type is better than plated.

In a previous life, I designed marine radios, so I had to know
something about galvanic corrosion and materials.

How many people do you know ride their bicycles across the sea?

"Sir Ridesalot" wrote in message
...
On Friday, June 9, 2017 at 10:38:47 PM UTC-4, Jeff Liebermann wrote:
Snipped
You can easily tell the difference. A2 is slightly magnetic, while A4
is non-magnetic:
https://www.youtube.com/watch?v=mbbXvvpoLCo
Snipped

Ah, that explains why mu stainless steel cookware would NOT work on my
induction stove = my stainless steel cookware was not magnetic.

A metal pan should behave like a shorted turn and get hot whether its
magnetic or not.

"Jeff Liebermann" wrote in message
...
On Sun, 11 Jun 2017 09:56:47 -0400, Frank Krygowski
wrote:

Sounds like the European Union really is in trouble.

Shssssh. Don't remind them. If they ever stop fighting each other,
they might decide to get organized and take us on. With our current
president as fearless leader, they would probably win.

With your present leader - anyone attacking you is probably superfluous.

On Monday, June 12, 2017 at 4:54:36 PM UTC-4, Ian Field wrote:
"Sir Ridesalot" wrote in message
...
On Friday, June 9, 2017 at 10:38:47 PM UTC-4, Jeff Liebermann wrote:
Snipped
You can easily tell the difference. A2 is slightly magnetic, while A4
is non-magnetic:
https://www.youtube.com/watch?v=mbbXvvpoLCo
Snipped

Ah, that explains why mu stainless steel cookware would NOT work on my
induction stove = my stainless steel cookware was not magnetic.

A metal pan should behave like a shorted turn and get hot whether its
magnetic or not.

Nope. On an induction stovetop the pot/pan has to be magnetic in order for the contents to get hot. the neat thing about an indion stove is thatthe pan/pot can get hot but an item sitting on the stovetop next to that pan/pot doesn't.

From: http://www.explainthatstuff.com/induction-cooktops.html

"induction cooking, uses electromagnetism to turn cooking pans into cookers (creating heat energy inside the pan itself, instead of firing it in from outside), which cooks food more quickly and safely with less energy.

What is induction?

Before you can understand induction cooking, you need to understand induction. And the first thing you need to know is that "induction" is a shortened way of saying "electromagnetic induction." In a nutshell, induction means generating electricity using magnetism. It stems from the simple fact that electricity and magnetism aren't separate, unconnected things (as we originally learn in school) but two different aspects of the same underlying phenomenon: electromagnetism.

An induction cooktop (a cooktop is called a "hob" in European countries) is simply an electromagnet you can cook with. Inside the glass cooktop, there's an electronically controlled coil of metal. When you turn on the power, you make a current flow through the coil and it produces a magnetic field all around it and (most importantly) directly above it. Now a simple direct electric current (one that's always flowing in the same direction) produces a constant magnetic field: one of the laws of electromagnetism is that fluctuating magnetism is produced only by a constantly changing electric current. So you have to use an alternating current (one that keeps reversing direction) to make a fluctuating magnetic field that will, indirectly, produce heat. And that's all that an induction hob does: it generates a constantly changing magnetic field. It does not generate heat directly. You can put your hand on top of it and you won't feel a thing. (Warning: Don't ever put your hand on a cooktop that has recently been used for cooking because it may have become dangerously hot from the cooking pan that's been standing on top of it.)

When you stand a suitable cooking pan on top of an induction cooktop that's powered up, the magnetic field produced by the cooktop penetrates the metal of the pan. So we have a fluctuating magnetic field moving around inside a piece of metal (the base and sides of the pan)—and that makes an electric current flow through the pan too (that's all that induction means).. Now this is not quite the same as the electric current that flows through a wire, carrying electrical energy in a straight line from (say) a battery to a flashlight bulb. It's a kind of whirling, swirling electric current with lots of energy but nowhere to go; we call it an eddy current. As it swirls around inside the metal's crystalline structure, it dissipates its energy. So the metal pan gets hot and heats up whatever food is inside it, first by conduction (it passes its heat energy directly to the food) but also by convection (liquid food rises and falls in the pan carrying heat with it).."

Cheers

On 13/06/17 06:51, Ian Field wrote:

How many people do you know ride their bicycles across the sea?

I once rode across a causeway that was covered by about 100-150mm of sea
water. Though I washed the bike with fresh water when I got home, the
ingress of sea water ruined both rims.

--
JS

John B. wrote:

Well, maybe. But on the other hand the guy
might be the size of a 600 pound gorilla
(from his posts he certainly exhibits the
brain power of one)

He is probably as intelligent a fighter as he
is an engineer. And all the while he'll be
thinking in there, I'll be hitting.

Why don't one of you native anglophones pose
a redneck corn-farmer and ask a beginner's
question on gmane.emacs.help ? We'll see if any
of the Scandinavians, Russians, Dutch etc.
take it upon himself to bring up American
contributions to Lisp, Emacs, and computers...

Anyway I've had it with this bubble. Thanks for
all replies, and also those who haven't been
written yet, this is very enlightening to me.

--
underground experts united
http://user.it.uu.se/~embe8573

John B. wrote:

Yes... but zinc plated would work outdoor
too. With perhaps a bit shorter lifetime.

And then we return to one of the questions in
my original post, namely, because those nuts
are cheap, and the difference between SS and
the rest not that big, why would anyone settle
for less? If you built something *huge* that
involved all but countless nuts and bolts money
would perhaps differ, but then again if you
ever built something that ambitious, wouldn't
it be all the more reason to get great gear,
especially on such a vital and basic area?

--
underground experts united
http://user.it.uu.se/~embe8573

On 13/06/17 08:21, Sir Ridesalot wrote:
On Monday, June 12, 2017 at 4:54:36 PM UTC-4, Ian Field wrote:
"Sir Ridesalot" wrote in message
...
On Friday, June 9, 2017 at 10:38:47 PM UTC-4, Jeff Liebermann
wrote: Snipped
You can easily tell the difference. A2 is slightly magnetic,
while A4 is non-magnetic:
https://www.youtube.com/watch?v=mbbXvvpoLCo
Snipped

Ah, that explains why mu stainless steel cookware would NOT work
on my induction stove = my stainless steel cookware was not
magnetic.

A metal pan should behave like a shorted turn and get hot whether
its magnetic or not.

Nope. On an induction stovetop the pot/pan has to be magnetic in
order for the contents to get hot. the neat thing about an indion
stove is thatthe pan/pot can get hot but an item sitting on the
stovetop next to that pan/pot doesn't.

From: http://www.explainthatstuff.com/induction-cooktops.html


Any metal pot acts as a shorted turn for sure, and air cored
transformers can work, but the driver coil in an induction stove top
cannot get enough magnetic flux to pass through the pot base without the
help of a material with high relative permeability (the ability to
create a magnetic field compared with a vacuum). It's more a problem of
geometry. Without a magnetic pot, the power that the induction coil is
trying to pass to the pot for heating is absorbed by itself. Really bad
idea. You'd cook the coil very quickly.

--
JS

On Mon, 12 Jun 2017 21:51:57 +0100, "Ian Field"
wrote:

"Jeff Liebermann" wrote
In a previous life, I designed marine radios, so I had to know
something about galvanic corrosion and materials.

How many people do you know ride their bicycles across the sea?

None, but a few acquaintances cross rivers, lakes, reservoirs, ponds,
canals, swamps, bogs, miasmic quagmires, puddles, etc:
https://www.google.com/search?q=aquatic+bicycle&tbm=isch
If you ride on salty roads, you should be concerned with corrosion.

Among "cruisers" that sail from harbor to harbor, folding bicycles are
quite common for shore transportation. Dahon makes the Mariner D7 and
D8 for boaters which is claimed to be corrosion proof.
http://dahon.com/bikes/mariner-d7/
http://dahon.com/bikes/mariner-d8/
There are others:
https://www.westmarine.com/buy/punch-corp--sailor-3-folding-bicycle--15062276
https://www.montaguebikes.com/folding-bikes-for-boats/
etc...

A friend bought one of these, on my suggestion:
https://www.google.com/search?tbm=isch&q=aquaskipper
http://inventist.com/inventions/aquaskipper/
It's not a bicycle. It does work, but requires quite a workout to
make it go.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

First let me apologize the last post, it came
across as me being angry with corn farmers,
Americans, etc. It was just an example that
came to mind. I was angry with one person and
should have left it with that. As for corn
farmers actually I always wanted to be
a peasant: outdoor life, always stuff to do
(possibly *too* much even!) Perhaps not corn
tho... God willing it might still happen.

Aaanyway... I looked into the catalogue from
the store again. They don't talk about
galvanization at all (only on the bags which
aren't rebranded), in the catalogue they
mention only different methods of "zinc'd", and
those are

"warm-zinc'd FZV" - I take it the
hot-dip galvanization.

"bright-zinc'd FZB" - galvanized, then some
esthetic polish? or something that
matters more?

"electro-zinc'd" - must be the
electroplated/zinc plated/electro-galvanized.

--
underground experts united
http://user.it.uu.se/~embe8573