Scale accuracy test report

Discussion in 'The Ammo & Reloading Forum' started by stev32k, Oct 31, 2012.

  1. stev32k

    stev32k Member

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    Attached are the results from my testing of the new scale I just received. In all five different tests were run: 1 Single weight - this is just what it says, checking the absolute accuracy of the scale against certified calibration weights; 2 Repeatability - weighing the same object over and over to check scale stability; 3 Additive/subtractive - adding and removing previously weighed objects to increase or decrease the weight. This checks the linearity of the scale ; 4 Tare 67.5 gr and add previously weighed objects. The tare weight is a fired .40 S&W case with the primer. Place the case on the scale and tare so the scale reads zero then add a previously weighed object on the case and record the weight. Test 5 is a repeat of test 4 using two fired cases.

    Test 4 and 5 duplicate how I will use the scale and also brings the weight into the upper more accurate range.

    Any comments?

    Attached Files:

  2. RandyP

    RandyP Member

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    Looks to me like the scale is WAY more accurate than an average reloader would ever need. Less than 1/10 of a grain is impossible to detect in operation I'm thinking.
  3. rcairflr

    rcairflr Active Member

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    I'm curious what scale you have, by the numbers posted, it appears your scale has a resolution of 1/100 of a grain.
  4. stev32k

    stev32k Member

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    It's this one:http://www.amazon.com/gp/product/B003STEJD4/ref=oh_details_o00_s00_i00

    Readability is .01 grains, but accuracy is about .02 grains as you can see from the test data. Just because one can read a number like .01 does not mean that the scale can tell the difference between .01 and .02.

    The weight needs to be higher to get the scale in an accurate range. The way to do that is put a weight like 150 gr on the scale then add the smaller weights. That will always be more accurate than trying to weigh say .1 or .2 grains by itself.
  5. RandyP

    RandyP Member

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    What I was suggesting is that all the load data I have only goes to 1 decimal point, so I pretty much ignored the scale table that went beyond that. .1 gr is almost insignificant, and fer sure .05gr is meaningless to me.
  6. 1LoneWolf75

    1LoneWolf75 New Member

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    I wish I had ANYTHIN that accurate!!!!
  7. LDBennett

    LDBennett Active Member

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    stev32k:

    Well!! You proved the nay sayers wrong. Very good indeed.

    When I saw the spec's you provided before, I though that the scale might actually be more accurate than any of the "Factory" scales. But all we really need is plus or minus a tenth of a grain. It is handy to know the scale is much more accurate than that.

    One of my Dillon scale's faults is drift off the zero over time. Even if I let it warm up for a hour or so or use it all day, it drifts off zero. No real problem in that my technique is to re-zero it for every measurement. I don't check my powder measure's delivery with every case and not even every tenth case as recommended because I trust the Dillon scale from years of use. I might check the powder measure's delivery half way through a batch of 100 or so. I have never found the charge off by more than a tenth grain or so. Every so often I check the scale against my Lyman test weights and it is always within a tenth grain accurate. Have you seen this drift problem with the new scale?

    The other failure is universal with all these digital scales: air drafts in the reloading area affecting the measurements. I use the "wind shield" when I can and place the scale away from any air drafts.

    Too bad the nay sayers won't come here and see the results of your buy. How foolish is it to think that only reloading companies can supply something as simple as a digital scale.

    Good luck with you new scale.

    LDBennett
    Last edited: Nov 1, 2012
  8. soundguy

    soundguy Well-Known Member

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    LD.. you are such a knowledgeable guy.. why be so condescending and myopic in your point of view?

    I was one that I guess you are lumping into the 'naysayer' range.

    I CAME hear and saw the results.

    Keep in mind that not all of us were saying that it was going to be an INACURATE scale.

    some of us mentioned that simply having an industry standard might be a better way to go vs liability.. whether or not the actual measurements were and more or less accurate.


    so much knowledge.. so narrow a viewpoint???

    free country i guess ( mostly ).. and everyone's entitled to say their piece... etc..

    soundguy

  9. stev32k

    stev32k Member

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    Sorry about the double post - didn't realize I had done that.
    Last edited: Nov 1, 2012
  10. stev32k

    stev32k Member

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    It does not seem to drift very much. I put a 170.02 gr bullet on the scale and let it set until the scale turned itself off - about 3 minutes then repeated that several times. The weight usually did not change any. Every now and then it would drift to about 170.04 or 170.06.

    I'm actually pretty amazed. twenty years ago a scale with that kind of range and accuracy would cost between $800 - $1200 and would need to set on a heavy pedestal made of marble to dampen vibration.

    I first learned about the scale from a jeweler. My daughter wanted a gold necklace and as I was looking at them I asked what one weighted and the jeweler brought out that scale. I was very skeptical because I have quite a bit of experience with analytical balances and used them for many years. So I didn't believe something that small could accurately weigh anything to the milligram level. The jeweler took me to the back and showed me his $3,000 Mettler analytical balance. He then weighed the necklace on both and got the same weight to within 3 milligrams. That was impressive.

    My question now is how long it will hold up and maintain accuracy.
  11. LDBennett

    LDBennett Active Member

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    soundguy:

    Some of the nay sayer beat up Steve pretty badly for straying from the fold and I pointed that out at the time. While you may or may not have been one, I am now pointing out that science won, not blind acceptance of the norm.

    I have view points on everything because I was trained that way as an engineer. I express those views based on experience and education, both formal and informal. I only come here to help others to not make the mistakes I made in reloading and guns in general. Believe me I have made a few mistakes along the way in 25+ years of guns and reloading. I don't have just one gun or have only had just one reloading setup. I am experienced and try to pass that experienced along. You can accept it or reject it. I really don't care. We all get to choose. But there is no reason, at least in my mind, to keep reinventing the wheel. We can learn from the experience and mistakes of others. If you don't like my comments and responses, you don't have to read them. I say it the way I see it and if you don't agree... oh well.

    LDBennett
  12. soundguy

    soundguy Well-Known Member

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    We may or may not have differing opinions. I'm an engineer as well.

    you don't see people using farm tractors out building roads.. they generally use normally accepted heavy equipment.

    can you build a road with a farm tractor? sure. :)

    I see some avenues not as mistakes.. but just different paths.

    You have too much info in your posts to NOT read them.. just stating that somtiems your brush gets pretty broad. I was int he discussion and thus guess I'm one of the naysayers you referred to.. yet the generalizations , some of which were made, do not apply to all.

    i seem to remember another user contemplating using a non reloader-branded scale a while back. the justice was swift and constant with the only reprieve being as I recall.. go ahead and get it an see how bad it is.. or blow yerself up.. or something to that extent. it was pretty universal too.. i didn't see much if any quarter given in the thread. ;) guess times are changing now.. :)

    just saying.

    ditto your last line.
    Last edited: Nov 1, 2012
  13. LDBennett

    LDBennett Active Member

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    soundguy:

    The "scale" in question is not the wrong tool for the job. It meets or exceeds all the requirement. Its only fault is that it is not sold by one of the reloading manufacturers.

    The focus of all the comment against stev32, after he made it clear that it did indeed measure grains, was that it was not sold by reloading manufactures. And some of those comments were pretty harsh. (I did not say all the commenters were nay sayers).

    Testing, the way of engineering, proved that the "Scale" would adequately do the job perhaps even better than the scales sold by reloading manufacturers. steve32 made it clear that he would test it, evaluate the results, and then decide to keep it or return it. That is a good engineering approach. If you indeed are an engineer and don't agree with that approach you need to review your old text books.

    Just because a reloading manufactures sells a tool does not mean that tool is the best tool or the only tool for the job.

    LDBennett
  14. soundguy

    soundguy Well-Known Member

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    OK.. at this poit.. i'll just have to stop conversing with you aftr that direct insult.

    I'll read your posts for the usefull info they contain, but will no longer be able to actually have a conversation with you.

    I specifically stated i was an engineer in no uncertain terms.

    The 'if' question afterwards is a tad insulting.

    later.

    I won't further reply to this thread topic.

    soundguy
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