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Accuracy of new coin scale

I just acquired a new coin scale that supposedly has an accuracy of 0.01g. It didn't come with a calibration weight so I have none, however, the scale will zero itself out on turning on. Not sure if this means much.

I placed a 1986 Silver American Eagle on the scale. It's documented to have a weight of 31.101g. My scale measured it at 31.16g (a difference of about +0.19%). I tried weighing it with a flip and without the flip...same exact weight.

Here's my question, is it about as accurate as I will get from most scales of 0.01g accuracy or do I need to return it?

Comments

  • derrybderryb Posts: 37,534 ✭✭✭✭✭
    weight different ASEs. There is probably some variation among them. Let us know the results of your experiment.

    If you find a particular year weighs more I would sure like to know. image
  • PrethenPrethen Posts: 3,454 ✭✭✭
    1987 (1)=31.40g
    1987 (2 - diff coin)=31.44g
    1987 (3 - diff coin)=31.25g
    1991=31.19g

    Unusual? Or, simply wrong?
  • epcjimi1epcjimi1 Posts: 3,489 ✭✭✭


    << <i>I tried weighing it with a flip and without the flip...same exact weight.

    Here's my question, is it about as accurate as I will get from most scales of 0.01g accuracy or do I need to return it? >>



    I would think a scale accurate to 1/100th of a gram should be able to discern the presence of a flip vs a coin weighed without a flip. I'd return it.
  • pruebaspruebas Posts: 4,588 ✭✭✭✭✭
    If you spent $40 on a made in China model, I wouldn't expect such accuracy. Just because it displays to 0.01g doesn't mean the weigh sensor is accurate in that range. There are different kinds of sensors, and the cheap scales use the cheapest parts. On such a scale, it's best to ignore the last digit completely, as it's meaningless. (This is proven out by the fact that there was no difference weighing the coin with and without flip.)
  • PrethenPrethen Posts: 3,454 ✭✭✭


    << <i>

    << <i>I tried weighing it with a flip and without the flip...same exact weight.

    Here's my question, is it about as accurate as I will get from most scales of 0.01g accuracy or do I need to return it? >>



    I would think a scale accurate to 1/100th of a gram should be able to discern the presence of a flip vs a coin weighed without a flip. I'd return it. >>


    I noted that with and without the flip the weight was the same for the coin (after subtracting the weight of the flip).
  • epcjimi1epcjimi1 Posts: 3,489 ✭✭✭
    ^^^

    Oh, I see. Never mind. image
  • PerryHallPerryHall Posts: 46,680 ✭✭✭✭✭


    << <i>1987 (1)=31.40g
    1987 (2 - diff coin)=31.44g
    1987 (3 - diff coin)=31.25g
    1991=31.19g

    Unusual? Or, simply wrong? >>



    Weigh these coins several times. If you get the same exact weights each time, your scale is probably quite accurate.

    Worry is the interest you pay on a debt you may not owe.
    "Paper money eventually returns to its intrinsic value---zero."----Voltaire
    "Everything you say should be true, but not everything true should be said."----Voltaire

  • TwoSides2aCoinTwoSides2aCoin Posts: 44,489 ✭✭✭✭✭
    The scale is new, but if the coin is not image
    It's amazing how much a coin wears away. Maybe weigh them when they're less than AU.
    Then instead of "Guess The Grade" with photos, we can do it in grams.
    As to the accuracy of the scale, Perry hit it on the head.
  • derrybderryb Posts: 37,534 ✭✭✭✭✭
    AU American Silver Eagles? image

    I'm gonna have to start asking my bank teller if she has any in the drawer!
  • KoveKove Posts: 2,038 ✭✭✭✭
    There's a big difference between "accurate to 0.01g" and "0.01g resolution" or "0.01g readability."

    I suspect your scale has higher resolution than it has accuracy. Lots of scales will post numbers down to 0.01g, but their accuracy is more like 0.05g, 0.1g, or is expressed as a +/-%.



  • AUandAGAUandAG Posts: 24,873 ✭✭✭✭✭
    I weighed a tube of ASE's from 1987 and only one weighed 31.1 on my digital scale.
    Mine is only one digit right of the decimal point. But, I now carry that ASE whenever
    I need my scale, as a check. Mine is made in China. Had it about 5 years and no
    problems whatsoever.
    When I weigh the same coin on my Ohaus Beam Scales it's exactly 31.1. I suspect
    that your new scale is dead on.

    Trick is finding a check weight or coin that you know the exact weigh on.

    bob

    image
    Registry: CC lowballs (boblindstrom), bobinvegas1989@yahoo.com
  • BarryBarry Posts: 10,100 ✭✭✭


    << <i>Weigh these coins several times. If you get the same exact weights each time, your scale is probably quite accurate. >>


    What you define is precision, not accuracy.

    image
  • TwoSides2aCoinTwoSides2aCoin Posts: 44,489 ✭✭✭✭✭


    << <i>AU American Silver Eagles? image

    I'm gonna have to start asking my bank teller if she has any in the drawer! >>



    I know a lot of fellows who keep one in their drawers.. image
  • PrethenPrethen Posts: 3,454 ✭✭✭
    Some more tests:

    2 newer BU Lincoln cents - 2.47g and 2.48g (documented weight=2.5g)
    3 BU state quarters - 5.69g, 5.71g, and 5.76g (documented weight=5.67g)

    I weighed each one at least 2-3 times and the weight came up the same each time for each.
  • TwoSides2aCoinTwoSides2aCoin Posts: 44,489 ✭✭✭✭✭
    Early on when the Chinese were first being used in manufacture for an American company, the requirement was no more than 15 parts per million could be defective. It was determined later that there were 15 parts per million failing.

    This was brought to the manufacturer's attention and the Americans were told that it was necessary to create the failures in their manufacturing environment, in order to meet the American standard.
    Go figure. That's "accuracy" and precision.
  • PerryHallPerryHall Posts: 46,680 ✭✭✭✭✭


    << <i>

    << <i>Weigh these coins several times. If you get the same exact weights each time, your scale is probably quite accurate. >>


    What you define is precision, not accuracy.

    image >>



    I understand and agree with what you are saying. My point was that if the scale was precise, that would be a good indication that it's a quality piece of equipment and would indicate that it's also probably accurate. It doesn't surprise me that the ASE's are slightly heavy. These coins have manufacturing tolerances and the mint purposely makes them slightly heavy so those ASE's that are on the light side of the tolerances still contain at least one full ounce of silver.

    Worry is the interest you pay on a debt you may not owe.
    "Paper money eventually returns to its intrinsic value---zero."----Voltaire
    "Everything you say should be true, but not everything true should be said."----Voltaire

  • DCAMDCAM Posts: 300 ✭✭✭
    You're talking about reproducibility, it may reproduce the same inaccurate number over and over.
    Buy More Coins!!
  • kruegerkrueger Posts: 900 ✭✭✭✭


    Kove and Au and AG are correct.

    To check the calibration of your scale Find a piece or two that are close to full scale values on the ranges of your scale.
    see if you can get them weighed by a lab or college student in a chemistry class
    with their very accurate scales (hopefully a good more accurate than 0.01 gm). Use these pieces with these measured values as your transfer check standards to see how much off your scales calibration is. You can if desired note the difference and apply it plus or minus as necessary to all your readings as a correction factor. These cheap scales may not be linearly accurate down scale so ideally a check standard at full scale and half scale would be better. Measurements at or near full scale are the most accurate. This should give you more confidence in your scales measurements.
    Buying calibration weights 4 to 10 times more accurate then your scale is way too expensive for what you are doing with it.

    Krueger
  • Prethen,
    I also have a coin scale that is suppose to be accurate to 0.01g. It comes with a calibration weight and I
    have found it to be accurate.
    If you want to compare notes, give me a call.

    Mark
    Member of LSCC, EAC, Fly-In Club, BCCS
    Life member of ANA
  • BAJJERFANBAJJERFAN Posts: 31,211 ✭✭✭✭✭
    Match grade bullets can be used as a good calibration weight. There are 7,000 grains and 453.59 grams in a pound so one gram is 15.4324 grains. A 180 grain match bullet will weigh 180/15.4324 or 11.664 grams.
    theknowitalltroll;
  • BAJJERFANBAJJERFAN Posts: 31,211 ✭✭✭✭✭


    << <i>Early on when the Chinese were first being used in manufacture for an American company, the requirement was no more than 15 parts per million could be defective. It was determined later that there were 15 parts per million failing.

    This was brought to the manufacturer's attention and the Americans were told that it was necessary to create the failures in their manufacturing environment, in order to meet the American standard.
    Go figure. That's "accuracy" and precision. >>



    Sounds like a failure to communicate. 15 ppm max should be a limit and not a standard. It makes little economic sense to make out of spec product on purpose just to achieve/approach an acceptable defect level. If they had a bunch of off spec stuff laying around I suppose they could blend it off rather than scrapping it.
    theknowitalltroll;
  • notwilightnotwilight Posts: 12,864 ✭✭✭
    How much did you pay for this high precision scale? Coincidentally I received in the mail today this little jewel.

    I paid $5.22 delivered and it weighs to .01 gram. I grabbed some pennies from my pocket and threw them on one at time, all around 2.5 gm untill one was 3.11 gram. Copper.

    So in response to this thread I weighted an ASE. 2011-W. 31.17 gm. I weighed several 100 grain Sierra Hollow point boat tail copper jacketed 6mm bullets and they all weighed 1.53 gm which would be .01 gm light but maybe accurate.

    I'm happy for $5.22. If you paid a lot more, maybe you should consider returning it and buying the one I bought.

    --Jerry
  • ambro51ambro51 Posts: 13,930 ✭✭✭✭✭
    Bah Humbug and a Pox on your newfangled toys. I've got a century old balance scale with weights and aluminum discs down to 1/2 grain. It is always correct and though slower to use its astoundingly accurate.
  • PerryHallPerryHall Posts: 46,680 ✭✭✭✭✭


    << <i>Bah Humbug and a Pox on your newfangled toys. I've got a century old balance scale with weights and aluminum discs down to 1/2 grain. It is always correct and though slower to use its astoundingly accurate. >>



    Sounds like the powder scale that I use.image

    Worry is the interest you pay on a debt you may not owe.
    "Paper money eventually returns to its intrinsic value---zero."----Voltaire
    "Everything you say should be true, but not everything true should be said."----Voltaire

  • notwilightnotwilight Posts: 12,864 ✭✭✭
    I also have a powder scale that is very accurate but isn't so quick, or cheap. --Jerry
  • PrethenPrethen Posts: 3,454 ✭✭✭


    << <i>How much did you pay for this high precision scale? Coincidentally I received in the mail today this little jewel.

    I paid $5.22 delivered and it weighs to .01 gram. I grabbed some pennies from my pocket and threw them on one at time, all around 2.5 gm untill one was 3.11 gram. Copper.

    So in response to this thread I weighted an ASE. 2011-W. 31.17 gm. I weighed several 100 grain Sierra Hollow point boat tail copper jacketed 6mm bullets and they all weighed 1.53 gm which would be .01 gm light but maybe accurate.

    I'm happy for $5.22. If you paid a lot more, maybe you should consider returning it and buying the one I bought.

    --Jerry >>


    Jerry, thanks for the info. I put that scale on my watch list. I'm still considering keeping my scale. But I must admit that your scale does seem very accurate.
  • AUandAGAUandAG Posts: 24,873 ✭✭✭✭✭
    Good info and I just bought the Jerry Scale as a back up to my 5 year old Chinese junker.

    Oh, how do you guys carry that balance beam to in home appointments???

    lol


    bobimage
    Registry: CC lowballs (boblindstrom), bobinvegas1989@yahoo.com
  • MrHalfDimeMrHalfDime Posts: 3,440 ✭✭✭✭
    "Bah Humbug and a Pox on your newfangled toys. I've got a century old balance scale with weights and aluminum discs down to 1/2 grain. It is always correct and though slower to use its astoundingly accurate."

    I couldn't agree more. Strongly stated, but the only way to go when seeking to accurately determine the mass of coins.
    They that can give up essential Liberty to obtain a little temporary safety deserve neither Liberty nor safety. Benjamin Franklin
  • ambro51ambro51 Posts: 13,930 ✭✭✭✭✭
    imageimage BTW a flip weighs 26.5 grains
  • AUandAGAUandAG Posts: 24,873 ✭✭✭✭✭
    My new "Jerry Scale" just arrived from China, took three weeks. But, all is very well and
    it's accurate per my beam scale and cheap, too!

    bobimage

    edited to add pic: image
    Registry: CC lowballs (boblindstrom), bobinvegas1989@yahoo.com
  • MikeInFLMikeInFL Posts: 10,188 ✭✭✭✭
    Thanks for the heads up guys, I've been looking for a good cheap scale for a while, and took the opportunity to order the "Jerry Scale" based on the recommendations in this thread. Appreciate it....Mike
    Collector of Large Cents, US Type, and modern pocket change.

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