yobbo II
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Vintage weighing scale
How accurate is this scale does anyone know?
Cheers,
Yob
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MadHatter
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Vintage Weighing Scale
Pictures ?
From opening of NCIS New Orleans - It goes a BOOM ! BOOM ! BOOM ! MUHAHAHAHAHAHAHA !
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ManyInterests
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I second that. We need pics or a link at least.
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Sulaiman
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url? Model #? Photo?
Or do we just use our psychic abilities?
CAUTION : Hobby Chemist, not Professional or even Amateur
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crow6283
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Based on the information given I recommend:
https://eightball.tridelphia.net/
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yobbo II
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OOOOO Very Funny!!!
I forgot the link.
https://www.ebay.co.uk/itm/125036242046?hash=item1d1cbda47e:...
Cheers,
Yob
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ManyInterests
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It says 1951 to present. But that looks so 19th century/early 20th century. If it is in good working order I suppose it would be fine for measuring
small amounts of chemicals. But why go for something that old for that purpose when much newer and better stuff exist.
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macckone
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My guess is it is probably a milligram scale.
The current accuracy is a function of maintenance.
It will probably need some maintenance to get to the best range.
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Sulaiman
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To use such scales you will need a full set of calibrated weights
which will add a significant cost.
For general use a cheap digital scale is adequate.
Generally, the weight range of a scale should match the scale of your glassware.
300g x 0.01g is generally useful
or 3kg x 0.1g for larger scale
etc.
CAUTION : Hobby Chemist, not Professional or even Amateur
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SWIM
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"There is a pendant that has snapped off but the pendant and string are still there."
"I don't know if they work or how they work or if there are pieces missing"
Looks like a risky purchase unless you understand how it works.
W and J George became W and J George and Becker in the early 50s and is now defunct, so information on this item may be hard to find (except maybe in
science and technology museum collections)
Since it is non-working, and being sold with no specified condition I'd wonder if any of those fine little parts might be bent, or if any bearings
might be worn to an extent that affects the accuracy.
I see a few little adjustment screws in there. Hopefully they turn freely, but what if they're stuck fast from old oxidized porpoise head oil, or even
worse, corrosion?
(Yes, they did use porpoise head oil for fine mechanisms in the 19th century)
I don't want to be a doom-cryer, but unless you're pretty good with fixing tiny, sophisticated mechanisms, or are willing to try talking a watchmaker
into giving it a go I'd give this one a miss.
I hate saying this as it is a beautiful little piece of equipment.
Edit: I asked the magic 8-ball if you should buy the scale and it answered, "Very Doubtful".
[Edited on 11-12-2021 by SWIM]
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unionised
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It's a work of art, or a conversation piece. I might buy it if I had more room in my house for collectables. It probably doesn't work. Resurrecting it
would be hard.
If you are looking for a frustrating project then buy it.
If you want a lab balance, a modern digital one will be better for the same price.
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yobbo II
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Thanks for replys.
Hard to know if it is the actual scales or the talking point associated with owening the thing I am looking for.
Nicer one here but I would like .1mg.
https://www.ebay.co.uk/itm/175048602314?_trkparms=amclksrc%3...
Yob
[Edited on 15-12-2021 by yobbo II]
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SWIM
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Quote: Originally posted by yobbo II  |
Hard to know if it is the actual scales or the talking point associated with owening the thing I am looking for.
[Edited on 15-12-2021 by yobbo II] |
I know exactly what you mean.
I've got a couple of pieces of equipment that were just too cool to not buy.
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pneumatician
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if the dishes are very clean and the needle is in the middle... precise enough...
My balance cracked... so i buy another digital shit, but this is the last, if the balance crack without any impact, corrosion... in a very few years I
never buy another digishit and go for one of this... I used in the school and I have memories of being quite accurate and easy to use. If I don't
remember bad this scale do down to 5-10mg... Anyway you use a weight element so...
Unless you spend 2500 to 6000 € the shit is the same :-)
you can get one of this, 200g 0.001 mg for 200€
https://gram-group.com/product/gram-fh/
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Ubya
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| Quote: Originally posted by pneumatician |
if the dishes are very clean and the needle is in the middle... precise enough...
My balance cracked... so i buy another digital shit, but this is the last, if the balance crack without any impact, corrosion... in a very few years I
never buy another digishit and go for one of this... I used in the school and I have memories of being quite accurate and easy to use. If I don't
remember bad this scale do down to 5-10mg... Anyway you use a weight element so...
Unless you spend 2500 to 6000 € the shit is the same :-)
you can get one of this, 200g 0.001 mg for 200€
https://gram-group.com/product/gram-fh/
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during my quantitative analytics course we tried this kind of balances (nostalgic professors)
and later we used this kind of balance with a single plate
they were pretty precise, if someone was walking behind me while i was weighting something i had to wait for them to stop otherwise the numbers
wouldn't stop oscillating (they had an error of +-0.1-0.2mg).
but, and this is a big BUT, you can't use them on normal tables, we had solid concrete tables on brick "legs" but still someone walking a few feet
near me would throw off the measurement. another "BUT" is that they are very VERY delicate, drop it or bump it too hard and it's easier to get a new
one. The arm rests on an agate knife edge, and they are so delicate you have two weighting modes, and messing them up can damage the knife edge
ruining the balance.
i won't go in detail on how these balances work, but long story short they are delicate, picky and to get a measurement it takes some time, it isn't a
"put the sample, read the number" kind of deal.
oh and about the 2 plates balance, the best measurements are takes with the "tare method" (no clue how it is translated),
the length of the two arms isn't the same, even for very precise balances, so you have to first ballpark in excess the weight of you sample. on plate
1 you put anything really of that weight (coins or real weights), then you put calibrated weights on plate 2 until they match in weight. Now you can
assume that the weight on plate 1 is the same you put on plate 2 (not true since if the arms are of different length the weights can be different, but
doing this we eliminate the unknown difference between the arms of the balance), remove the calibrated weights on plate 2 and put the sample you need
to measure and add weights until the two plates equilibrate again. to know the mass of your sample you remove from the weight on plate 1 the weights
you added to plate 2 (the one with the sample).
in the end all balances can perform the same, some mechanical balances are even more precise than digital ones, but even though i like the feeling of
taking measurements the old way, i want to put as much focus as i can on my project, not in weighting samples.
that lab i did was very interesting, but after weighting 5 samples per titration, and each sample had to be weighted 5 times to calculate the average,
i'm really happy with my milligram digital scale xD
just a pic to show how amazing these mehanisms are
---------------------------------------------------------------------
feel free to correct my grammar, or any mistakes i make
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Sulaiman
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good luck getting 200g x 0.001 mg for 200euro
pneumatician meant 0.001g (1mg)
P.S. I have a triple beam balance just because I like the look of it
Mechanical analytical balances are wonderful
but the knife edges are critical items for accuracy
and easily damaged ... caveat emptor.
Two pan balances need a full set of calibrated weights, and are tedious to use
but a good unit can outlive us all.
Single pan mechanical balances have inbuilt weights and are quicker to use,
but they are more difficult to re-calibrate or repair.
If possible arrange to collect in-person so that you can check it over, especially the knife-edge bearings.
Be sure to raise the bearings before transport.
[Edited on 27-12-2021 by Sulaiman]
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pneumatician
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thanks, i get this far
where is the problem? 200g x 0.001 mg for 200euro???
my last balance is 300g, 0.001 mg imported from Canada for 250€ from Acculab Vicon now absorbed by Sartorius group...
of course if you buy a analitical balance you need a good table...
this is like putting a expensive and good telescope in your terrace... no no my friends... you need to put the telescope's food column over a big
column of the building, because if you want to take photos with minutes of exposition... pray nobody come to the terrace, the elevator is not used, a
knock on the door... and your pics are ruined.
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DraconicAcid
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| Quote: Originally posted by pneumatician |
where is the problem? 200g x 0.001 mg for 200euro???
my last balance is 300g, 0.001 mg imported from Canada for 250€ from Acculab Vicon now absorbed by Sartorius group... |
0.001 mg is a microgram. You are not going to find a balance that measures up to 200 g with a precision of a microgram.
+/- 1 mg is reasonable for a 250 euro balance. +/- 0.001 mg is not.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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pneumatician
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| Quote: Originally posted by DraconicAcid |
0.001 mg is a microgram. You are not going to find a balance that measures up to 200 g with a precision of a microgram.
+/- 1 mg is reasonable for a 250 euro balance. +/- 0.001 mg is not. |
microgram?? click in Technical features!! All the balances called "precision balances" have this price range aprox. and all say 0,001 g. Well some
"precision balances" of this range 100-500 gr 0.001 mg have a price of around 1000€ but I think is a mere marketing thing.
https://gram-group.com/product/gram-fh/
FH-200 FH-2000
FH-6000
Capacity (g)
100
200 2000
6000
Readability accuracy (g)
0,001
0,001 0,01
0,1
Linearity (g)
± 0,001
± 0,001 ± 0,01
± 0,1
Repeatibility (g)
± 0,001
± 0,001
https://duckduckgo.com/?t=ffab&q=microgram&ia=answer
[Edited on 27-12-2021 by pneumatician]
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DraconicAcid
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| Quote: Originally posted by pneumatician | | Quote: Originally posted by DraconicAcid |
0.001 mg is a microgram. You are not going to find a balance that measures up to 200 g with a precision of a microgram.
+/- 1 mg is reasonable for a 250 euro balance. +/- 0.001 mg is not. |
microgram?? click in Technical features!! All the balances called "precision balances" have this price range aprox. and all say 0,001 g.
|
Yes, 0.001 g. You've been writing 0.001 mg. If you can't tell the difference, have some more caffeine and read it again.
[Edited on 27-12-2021 by DraconicAcid]
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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pneumatician
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one is what balance range or can weigh and the other is what balance display, and what process your brain etc... I have to give everything chewed??
this is obvious :-) ok if my scale say, hey guy you have 0.005 GRAMS, I do not say the same the scale say, I don't know about you , but I say, I've 5
MILLIGRAMS no matter the scale or the rest of the universe say :-) because I want to weigh milligrams and not g, no grAINs, no kg... for this reason I
buy a balance capable of this accuracy my friend, grams too, but with MILLIGRAM accuracy, obvious enough??? so this scale can read from 1 milligram to
200 grams, I can past from g to mg, Oz, Ct... or get the manual and play with the balance setup and change the balance units but oh, no milligrams
units because 200 gram = 200000 milligram, too much display to show and maybe if the scale weigh 200 g in mg the accuracy is the same??? is it
practical?
when you work with substances all in milligrams you write something like 0.001 g / 0.011 g / etc or 1mg, 11mg etc?? are milligrams something tabu for
you only because the display of the scale say 0.XXX g?
well I think is very clear and obvious, if not, check around you, in meds... if a pill have 500 mg of a chemical the paper, in general, do not say
500mg, and not 0.500 g or 0.0005 kg or etc.
well for your peace of mind, think I made a mistake or I don't have any idea of what I are writing here :-) maybe you mentally work normally with 5-10
units of weight, I work with 25+
maybe if I get something "indestructible" stable... I make my own units of weight and I do not lost more time with this crazy values making one little
code to translate to my own units :-)
and speaking about this, someone have access to 2 different balances and weigh the same sample and both scales say the same numbers??? on the scale of
milligrams. I'm afraid of no more nonsense like grease stains on fingers and so on for explain differences in the results, of course test the sample
in a balance and do not put your fingers in your asshole and get the sample, put in the other balance and come here to say, the weigh is not the same
:-)
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DraconicAcid
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| Quote: Originally posted by pneumatician | | one is what balance range or can weigh and the other is what balance display, and what process your brain etc... I have to give everything chewed??
this is obvious :-) ok if my scale say, hey guy you have 0.005 GRAMS, I do not say the same the scale say, I don't know about you , but I say, I've 5
MILLIGRAMS no matter the scale or the rest of the universe say |
But you haven't been saying 5 milligrams. You've been writing 0.005 mg when you mean 5 mg or 0.005 g. That's why we've been correcting you.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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yobbo II
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There is some strange glitch with the board.............
Anyhow...
Obtained the weighing scales.
They seem to be very sensitive. Weighing a four mm piece of 46 S.W.G. enameled copper wire moves the pointer around 4 notches.
From an old book I got a figure of around 0.00028 grams per MM (calculating backwards from a pounds per 1000 yards figure) of the wire giving the
scales a resolution (all approx.) of 280 micro grams.
The scales may in ounces?? Do old scales come in fractions of ounces (grains?).
Is this a fair way of putting it. I am only weighing the 4 mm of wire and not, say, a one gram weight + the 4 mm of wire.
I have no calibrated weights.
I am missing a weight which can be moved from the outside via a knob on the
casing. What weight should this weight be?
The picture does not show the scales set up correctly BTW. It shows a pan (or string to the pan) hanging on the hook of the mechanism of what moves
the missing weight along a graduated scales.
Thanks for you time.
Yob
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DraconicAcid
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The scale have to be in grams. Imperial units are always in fractions/multiples of 2 and 3, never 10 (so eighths, twelfths, sixteenths, etc).
For calibrating weights, use coins. You can look up the standard masses of the coins of various nations online (wikipedia, or the mint's website).
Other than that, I have no advice to give.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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