[meteorite-list] Scales - Looking for Advice

From: Michael L Blood <mlblood_at_meteoritecentral.com>
Date: Sat, 09 Dec 2006 07:36:22 -0800
Message-ID: <C1A017F6.312A5%mlblood_at_cox.net>

Hi Norbert,
        You write, "I'm looking for an affordable but precise digital
pocket scale." In some ways, the qualities you seek are mutually
exclusive. You want:
1) Portable
2) "Precise" (a variable term)
3) "Affordable" - also a variable term.
        Let me share my own experience regarding the exact same
desires and also what I have seen:
        I own a 4 KG scale accurate to within .1g - However, I had to
pay to have it "calibrated" exactly where it sits in my office and
not move it for it to remain "stable" and predictable in its accuracy.
(according to the calibrator, who spoke of various factors such
as how close other metal objects are as well as NEVER moving
the scale). This scale costs over $1,000 new, though I got it used
and paid for factory refurbishing and then calibration on site for
much less, as a friend sold it to me for like $75 without one of the
parts, which I easily replaced from the manufacturer.
        At the other extreme, I have a scale that goes to 120g. This is
 also a non-portable scale and weighs to 1/1,000th of a gram and
cost me about $5,40.
        Third, I have a portable (battery driven) scale that weighs up
to like 200 Kg. It is amazingly light for what it does and only cost about
$100, though I do not know how precise it is. It is, of course, for big
irons or gigantic stones, and I take it to the show - I keep it in the
motor home, as I have infrequent use for it in the office. It is "portable."
        The 4th scale I use is closer to what you want: It is a Tanita
portable (Model #1481) and cost me $42.50. It is VERY slim, metal, light
and fits easily into a shirt pocket. They list for $89 or $99 on the Tanita
site, but several dealers offer them on eBay new and "in the box." One
offers hem for the incredible price of $42.50. It will weigh up to 120g at
1/10th of a gram. I have not compared this new one with my 4Kg scale,
but the old Tanita I had for years weighed exactly to the same 1/10th
gram as the stationary scale that was calibrated.
        None of these are likely to be what you want, but generally
demonstrate the range in prices and the problem presented with
a mobile unite combining fine measurement with low price. At the show,
I have seen many units that claim to measure to the 1/100th of a gram
with accuracy with similar mobility. I think they are about $120. You
can even get a small, but not truly pocket portable unit that will go
to 1/1,000 th of a gram and are said to be "inexpensive" - but I am
not clear what that means.
        You would likely be best satisfied with a truly portable unit that
measures to 1/100th in the $100 cost range, but only you would know
for sure.
        Best wishes, Michael
                

on 12/8/06 4:18 PM, Norbert Classen at trifid at timewarp.de wrote:

>
> Hi All,
>
> I'm tired of visiting the petrologic lab of our local university each time I
> want to accurately weigh a new sample. Besides that, I would love to have a
> small but precise portable scale that I could carry to the shows...
>
> Since I'm mostly into micros, and more rare meteorites, such as lunar or
> martians, I'm looking for an affordable but precise digital pocket scale,
> best with 1mg or 2mg resolution, and now I'm wondering how accurate the more
> common gem and diamond scales actually are. Does anyone of you, collectors
> and dealers, have some experience with the accuracy, and properties of one
> of the following scales?
>
> - Gempro 50 (My Weight)
> - JS-VG 20 (Jennings)
> - JPG 10 (JScale Precision/Jennings)
>
> These are the ones that seem to be more common. Would you recommend the one
> or the other? Any other scales that you could recommend?
>
> Thanks for your input, and for your advice!
>
> All the best,
> Norbert
>
> http://www.meteoris.de/
> Planetary Meteorites
>
>
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Received on Sat 09 Dec 2006 10:36:22 AM PST