I looked on ebay for a calibration weight to test my scales for accuracy, and found a set of 5 weights that could be used in multiples to create a wide variety of weights from 5g to 105g. I bought a set expecting them to be a bit random, but when tested on different scales they do seem to be very accurate.
I couldn’t imagine why you had a sample card of snaps!?!
I had one of those tiny scales in the dye room…it was good, down to.001grams, it claimed, and seemed to be pretty accurate, until the battery got low!
Fortunately, the reading it gave then were so ridiculous, it was obvious it needed new batteries!
About scales: Think how you make a scale that can measure from 100g to 20kg with 50g accuracy but at the same time withstand 200kg? Those were the scales we had in international mail in Finland. The international agreement was that air mail would measured from 100g up to the maximum of 20kg with accuracy of 50g. But as practical safeguard Finland Post understood that everyone would like to weight themselves on these scales because as airmail bag scales they were big enough to a human stand on them. There was only one scale manufacture in Finland which could make those and there were not cheap. But consindering to ask someone to come and calibrate your scale because it was used to weight a human was even more costly. This was in 90's. Don't know what it is now as the airmail moves not in bags but in receptacles.
You will get arrested as a drug dealer with one of those scales, be careful Clive 🙂
Even in a lab environment we dont always have to worry about absolute accuracy as much as linearity, as in the ability to be accurate and similarly accurate, throughout the scales range. If a scale is 1% out then its not so bad as long as its 1% out all the time, and consistently 1% out (so always over for example).
That way everything you weigh on it will be in proportion. What you dont want is something 1% under at 10g and 1% over at 100g. If you check a scale at the top, middle and bottom of its range it needs to be consistent, if it varies wildly in the middle its also no good.
I think the reason you're not supposed to touch them isn't because your greasy fingerprints add weight; it's because contamination from your skin can potentially cause corrosion, and that can lead to loss of mass over time. Altho I don't know if there's any practical loss of mass for the level of accuracy a user looking for cheap calibration weights would need to be concerned about, it probably is going to be an impact in the 3 or 4 decimal range if I had to guess [I don't think most folks are worried about their scales being like 0.0007g off]
Thats how decent calibration weights come, i worked in fords foundry Leamington spa. It was more my dads job ghat used them he tested sand so the cores dont split when being knocked out. At that time by a deezer matic line. Not spelt correct. Got a obscure German spelling.
The weights are not accurate at all. The 10g is out by 0.2%, the 20g one is out by 0.1%, and the 50g is out by 0.02%. Only the 50g one can be considered an M3 class weight, which should have a tolerance within 0.05%. Mind that the M3 class is the least accurate class that can be used for calibration.
Any gurus on here know how to calibrate Avery FX-142 scales ?
It is important to note the local gravitational field, distance from the equator etc… these all impact the total weight read; particularly when dealing with the very very tiny weights. From experience: being off by 0.1 to 0.01 to 0.001 factor is easily caused by latitude. There's a video floating around on YouTube of a private jet pilot / turbo-nerd, who took a 500g calibration weight & measured the change in apparent weight whilst flying East <—> West. I forget the exact figure but it was a difference of around 10 grams or so.
With those scales you can't really verify the weights. Beside I find most scales – event the 0,01 gram resolution ones are not the best. Of 4 such scales I got only 1 reliably reproduce the same results. Funny enough it's a cheap cigarette themed scale, Marlboro (not Manlloro), from a Chinese gadget site. On that scale all my calibration weights are dead on – after calibration. 5, 10, 50, 100, 200 grams all perfectly dot-zero-zero – even the Banggod and DX weights. Such scales need calibration form time to time as they will drift with time – the most right after manufacture. Kitchen scales are generally not that great so those you got there are great.
So yeah. Either all my weights are off by same percentage or they're actually quite good. More than good enough for .01 gram scales for private use.
Another great scale I got is a Kern 440-47N I dumbster dived. "Only" a 0.1 gram (2000g max) but it just gives a quality impression. I have two cheap 500g weights (2x 1000g) sets on the way so I can calibrate it properly. It can use 500, 1000, 1500 and 2000 gram for calibration. I have calibrated it using 500 gram and many(!) chinese weights but I want it a little better. 1000g weight I have trouble finding great ones at reasonable price and even more so 2000 gram – if they're to be shipped so for the moment I'm settling for 2x 500 which should be more than adecate for a 0.1 gram scale at halfway calibration. There was of course a reason it was thrown out. The 9v battery clip had become broken and battery door had become missing a long time ago (lots of tape residue). It got a thorough clean, a new battery clip and I made a new battery door – if not as good as new it's very close. And it's not exactly a cheap scale – definitely one of my better dumpster finds.
That's shit..what if I want to weigh up wraps of crack at 0.2 a bag and they are 0.1 /0.2 out
but how accurate is that scale?
Nice video.
Love that counting idea.
You must recalibrate ebay scale, pressing unit button with power button on (text "CAL") and then again unit button (text "CAL" blinking moment and ask calibrate weight). Then put scale max weight 200g or 500g and when pass text appear, scale is calibrated. Used buttons can vary.
Normaly drug dealers use coins to try there scales out