## Re: [Error Coin Information Exchange] Re: PS: More on that SLQ error

Expand Messages
• I know, I was only joking. I would probably have to relearn it in a few years also. ... __________________________________ Yahoo! FareChase: Search multiple
Message 1 of 14 , Oct 28, 2005
I know, I was only joking. I would probably have to
relearn it in a few years also.

--- Mike Diamond <mdia1@...> wrote:

> I was merely describing a shape, using the closest
> geometric form.
> But I'm sure you're aware of that. My geometry is
> probably as rusty
> as yours. But with my daughter just having entered
> Junior High, I'll
> have the pleasure of relearning it all over again.
>
> Geometry is of inestimable value in, for example,
> calculating the
> expected weight of any wrong stock error. It's also
> useful in
> calculating expected densities of alloys for which
> no SG value has
> been published.
>
> --- In errorcoininformationexchange@yahoogroups.com,
> Al
> <bull102797@y...> wrote:
> >
> > So, if, in a triangle, angles a, b, g lie opposite
> the
> > sides of length a, b, c, thensign(a + b - g) =
> sign(a2
> > + b2 - c2)
> >
> > --- Mike Diamond <mdia1@a...> wrote:
> >
> > > To be more precise, the shape is that of an
> > > isosceles trapezoid.
> > > This link with provide a precise definition.
> > >
> > >
> http://mathworld.wolfram.com/IsoscelesTrapezoid.html
>
>
>
>

__________________________________
Yahoo! FareChase: Search multiple travel sites in one click.
http://farechase.yahoo.com
• ... I don t know why I said this. Simple algebra (calculating a weighted average) is what I use to arrive at an expected specific gravity. I inevitably come
Message 2 of 14 , Oct 28, 2005
--- In errorcoininformationexchange@yahoogroups.com, "Mike Diamond"
<mdia1@a...> wrote:

> Geometry is...also useful in
> calculating expected densities of alloys for which no SG value has
> been published.

I don't know why I said this. Simple algebra (calculating a weighted
average) is what I use to arrive at an expected specific gravity. I
inevitably come up with the same values as those that have been
published. All you need to know is the SG of each metallic element
(easily found on the internet), and the percentage of each element used
in the coin.

Since published tables occasionally have mistakes, you can easily
double-check the SG values yourself.
• One note when doing sp grav tests, use room temp. distilled water ... has ... weighted ... I ... used
Message 3 of 14 , Oct 29, 2005
One note when doing sp grav tests, use room temp. distilled water
--- In errorcoininformationexchange@yahoogroups.com, "Mike Diamond"
<mdia1@a...> wrote:
>
> --- In errorcoininformationexchange@yahoogroups.com, "Mike Diamond"
> <mdia1@a...> wrote:
>
> > Geometry is...also useful in
> > calculating expected densities of alloys for which no SG value
has
> > been published.
>
> I don't know why I said this. Simple algebra (calculating a
weighted
> average) is what I use to arrive at an expected specific gravity.
I
> inevitably come up with the same values as those that have been
> published. All you need to know is the SG of each metallic element
> (easily found on the internet), and the percentage of each element
used
> in the coin.
>
> Since published tables occasionally have mistakes, you can easily
> double-check the SG values yourself.
>
• In a message dated 10/29/05 10:34:38 A.M. Central Daylight Time, RichErrors@aol.com writes: One note when doing sp grav tests, use room temp. distilled water
Message 4 of 14 , Oct 29, 2005
In a message dated 10/29/05 10:34:38 A.M. Central Daylight Time, RichErrors@... writes:
One note when doing sp grav tests, use room temp. distilled water

1. using a vibration-free table
2. making sure the surface the balance is resting on is perfectly level
3. tapping the submerged coin and its holder to liberate any micro-bubbles
4. use a balance accurate to at least the nearest .01 grams, and preferably .001g.
5. do multiple tests to reduce random fluctuations in SG value
6. test a sample of normal coins to establish a range of variation

SG is simple in concept, but tricky to execute well.

• These tips are in order for SG measurement. See below for other desirable tips. ... Also take into consideration wind gusts. Balance should be protected from
Message 5 of 14 , Oct 29, 2005
These tips are in order for SG measurement. See below for
other desirable tips.

--- mdia1@... wrote:

>
> In a message dated 10/29/05 10:34:38 A.M. Central
> Daylight Time,
> RichErrors@... writes:
>
> One note when doing sp grav tests, use room temp.
> distilled water
>
>
>
> 1. using a vibration-free table

Also take into consideration wind gusts. Balance should be
protected from ANY movement whatsoever.

> 2. making sure the surface the balance is resting on is
> perfectly level
> 3. tapping the submerged coin and its holder to liberate
> any micro-bubbles.

And...letting the balance stand in the wet measurement for
about a minute or so would allow bubbles to break up some
more.

> 4. use a balance accurate to at least the nearest .01
> grams, and preferably .001g.

The more precise a balance is the more reproducibility in
the final SG calculation.

> 5. do multiple tests to reduce random fluctuations in SG
> value
> 6. test a sample of normal coins to establish a range of
> variation.

The use of a "standard" coin whose SG is known to a much
higher degree is a great advantage for calibration
purposes. Since you know this SG to a very precise level,
the running of this coin's SG in your system will easily
tell how good is it.
The use of calibration weights for your balance might be a
good idea. If your balance is not retrieving weight
consistently throughout the range, your results will vary
widely.

> SG is simple in concept, but tricky to execute well.

Yep. It sure is.

__________________________________
Yahoo! Mail - PC Magazine Editors' Choice 2005
http://mail.yahoo.com
Your message has been successfully submitted and would be delivered to recipients shortly.