Just saw these at fasttech
http://www.fasttech.com/products/1410/10000979/1153601
I don’t fully trust anything without independent verification, especially anything I buy. I don’t think the Chinese could have become the world industrial and economic leader that they are with wrongly calibrated weights.
That made me laugh!
So your saying if SI sent them a rigged IPK they could collapse the chinese economy?
We got all these rules of war backwards, why use weapons when you can use a decalibrated kg to destroy an empire! 
Buy one and send it to me… I have scales that can measure 200 grams down to 10 micrograms (20 grams to a microgram. With new glass in my mass comparator I could measure it a microgram.
I once worked on building a scale that could measure 1 gram to a nanogram (!)… yep a 30 bit mass-to-digital converter.
But then i am paying for it, plus shipping to me afterwards because i can’t trust that two different samples from their shop are close to identical weight, making it easily triple the price 
Has anyone ever done a study of weight changes caused by shipping?
These don’t state what material they are, i would assume iron
I used 4 decimal analytical scales in college, i could knock on their door to weigh these
I think I still have a 90 year old analytical balance in the loft. But I'd suspect the worst standard weights from anywhere are more reliable than 90 years of dust and corrosion. Likewise for its weights.
hence the reason thread exists, humour is quite entertaining
I recently got the 100g and 5g… they show signs of calibration (material ground off) and on our primitive scales, they weigh approximately what they’re supposed to weigh.
I suppose I could send them along to TP, but wouldn’t that be the worst kind of statistics?
I was always interested in a cheap digital scale but always were suspicious…any recommendations?
How accurate are these gunpowder scales? I guess you will find a reloaded in every neighborhood which can check your weight…
besides that I don’t think shipping changes a weight in a reasonable way, if you are afraid of that you weren’t allowed to touch the weight with your hands too.
well , this 1kg sphere is not available yet…
Ah! There aren’t any more the weights of the old times 
You’d be surprised at the $3-$4 pocket scales. Not saying they’re super accurate but given the cost equals to some pocket change - it’s very impressive.
I have a few cheap scales bought from several places (ebay, BIC) and am still impressed at the repeatability of these things. My 10g weight (also chinese) always show very close result within all of them. And no, I didn’t calibrate them with that weight, that would be stupid to compare… 
no, I just used them as is.
Well, at least that goes to show they were calibrated after all.
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That sound promising, I don’t expect super fancy results but I would like at least half a gram precision or so…
Which one did you buy? How much max weight and how much precision?
I wonder if the 0.01g rated are really more precise or if they only have one display digit more….?
A higher max weight would be more universal but this also reduces the precision…
What about this
Description is promising…
@texaspyro
Have you ever measured some duracells or eneloops, how consistent are there weights? Maybe we could use this as a global calibrating base?
The Chinese use their own system of “calibrated tools” for measuring lumens, battery capacity….
Do you really trust them enough to buy their calibrated weights… ?
I am not sure how these calibration works, but I guess there an option to adjust the showed value to a known value.
You can easy find out how exact this weight is with measuring it on a better scale.
I talked to a gun reloader and he said his scale is advertised with 1/10 grain accuracy and if I once have a scale he would be happy to help me out.
You also could go to a jeweler, I guess these have also nice precise scales.
Am I correct with this hypothesis?
If so I just could ask a jeweler/pharmacist to weight something for me and calibrate my chinese scale to this…
Edit: just checked a manual from such a scale and it seems that there is just a calibrating option for 100g, 200 or 500g
And to get the best results you have to calibrate the scale before using them.
So a calibration weight at home seems necessary.
But you always could check the Chinese weights on a better scale at a calibrated scale from jeweler, drugdealer or butcher.
just use a nickle... costs 5 cents and weighs 5g. always worked fine for my application
All those standards are defined in terms of the properties of matter and physical phenomena. The distance standard, for example, is no longer the bar in Paris. It is defined as the distance light travels in a given amount of time. Secondary length standards are wavelengths of light given off by gases. Those are established by super heterodyning in stages all the way from visible to microwave radiation to compare to the time standard, which is more accurate than any independent length standard. There are Chinese physicists who can do that sort of thing. I have not read how weight is defined now, but it is no longer an object either.
i really think it’s still an object, work is done to redefine the kg, but is not finished yet.
Proper weights are a special alloy of stainless steel with a density of 8 grams/cc. It is also highly non-magnetic. The density specification is important because the major error in precision weighing is air buoyancy effects. Ultra-precision weighing is done in a vacuum. That nanogram res scale was a vacuum. Another effect can be heat radiated from your body. My microgram scale has three layers of special coated glass.
Also gravity is an important issue. I can easily measure the change in weight of an object caused by lifting it one meter.
Cheaper weights may be brass or plated brass.