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<p>[QUOTE=&quot;-jeffB, post: 2376324, member: 27832&quot;]About.com claims, without citation, a tolerance of +/- 0.259g for the 1964 Kennedy. (Oddly, they say current silver proof halves have a tolerance of +/- 0.400g.) As [USER=66]@Conder101[/USER] indicated, tolerances for clad coins are apparently +/- 4%.</p><p><br /></p><p>I&#039;m thinking about tolerance issues as well, so I weighed each coin in a new roll of 1964 Kennedy halves I just received. These are all BU or sliders.</p><p><br /></p><p>I actually went through the whole roll four times, top to bottom, then bottom to top, then back and forth again. So I went down the first column, up the second, down the third, then up the fourth. This was to make sure there wasn&#039;t any kind of &quot;stickiness&quot; between one weighing and the next.</p><p>[table]</p><p>[tr][th]Coin[/th][th]First[/th][th]Second[/th][th]Third[/th][th]Fourth[/th][/tr]</p><p>[tr][th]1[/th][td]12.49[/td][td]12.48[/td][td]12.48[/td][td]12.48[/td][/tr]</p><p>[tr][th]2[/th][td]12.47[/td][td]12.47[/td][td]12.46[/td][td]12.46[/td][/tr]</p><p>[tr][th]3[/th][td]12.58[/td][td]12.58[/td][td]12.58[/td][td]12.57[/td][/tr]</p><p>[tr][th]4[/th][td]12.53[/td][td]12.53[/td][td]12.53[/td][td]12.53[/td][/tr]</p><p>[tr][th]5[/th][td]12.37[/td][td]12.38[/td][td]12.37[/td][td]12.37[/td][/tr]</p><p>[tr][th]6[/th][td]12.35[/td][td]12.34[/td][td]12.34[/td][td]12.34[/td][/tr]</p><p>[tr][th]7[/th][td]12.63[/td][td]12.62[/td][td]12.63[/td][td]12.63[/td][/tr]</p><p>[tr][th]8[/th][td]12.52[/td][td]12.52[/td][td]12.53[/td][td]12.51[/td][/tr]</p><p>[tr][th]9[/th][td]12.35[/td][td]12.35[/td][td]12.34[/td][td]12.33[/td][/tr]</p><p>[tr][th]10[/th][td]12.62[/td][td]12.63[/td][td]12.62[/td][td]12.61[/td][/tr]</p><p>[tr][th]11[/th][td]12.64[/td][td]12.65[/td][td]12.65[/td][td]12.64[/td][/tr]</p><p>[tr][th]12[/th][td]12.42[/td][td]12.42[/td][td]12.42[/td][td]12.41[/td][/tr]</p><p>[tr][th]13[/th][td]12.74[/td][td]12.74[/td][td]12.74[/td][td]12.73[/td][/tr]</p><p>[tr][th]14[/th][td]12.32[/td][td]12.32[/td][td]12.31[/td][td]12.31[/td][/tr]</p><p>[tr][th]15[/th][td]12.61[/td][td]12.6[/td][td]12.59[/td][td]12.59[/td][/tr]</p><p>[tr][th]16[/th][td]12.32[/td][td]12.32[/td][td]12.31[/td][td]12.31[/td][/tr]</p><p>[tr][th]17[/th][td]12.31[/td][td]12.31[/td][td]12.31[/td][td]12.3[/td][/tr]</p><p>[tr][th]18[/th][td]12.61[/td][td]12.61[/td][td]12.61[/td][td]12.61[/td][/tr]</p><p>[tr][th]19[/th][td]12.47[/td][td]12.47[/td][td]12.47[/td][td]12.47[/td][/tr]</p><p>[tr][th]20[/th][td]12.41[/td][td]12.41[/td][td]12.41[/td][td]12.41[/td][/tr]</p><p>[tr][th]Avg[/th][td]12.488[/td][td]12.4875[/td][td]12.485[/td][td]12.4805[/td][/tr]</p><p>[/table]</p><p><br /></p><p>There&#039;s a slight downward drift over the course of the experiment, sharper in the last column. The whole process took about 20 minutes, and I&#039;m still using the batteries that shipped with the scale, so low voltage may have been affecting measurements. But it still looks like I&#039;m seeing a pretty solid +/- 1 digit repeatability.</p><p><br /></p><p>The overall average weight is a bit under the standard 12.5g, but while statistics has never been my strongest subject, I&#039;m pretty sure 12.48525 (for all four columns) or 12.48683 (throwing out the last column) is well within the expected range for a sample size of 20. Even if the actual average weight of the roll is exactly 12.5g, the scale is only off by 1.5 digits at most, which is (IMHO) spectacular for a not-recently calibrated cheap consumer scale. (Of course, the actual weights <i>could</i> be higher, and my scale <i>could</i> be off by more than I think.)</p><p><br /></p><p>I&#039;d been meaning to do a test like this for a long time. Now I know why I was putting it off. <i>Man</i>, that was tedious. But now I know a lot more about my scale. <img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie1" alt=":)" unselectable="on" unselectable="on" />[/QUOTE]</p><p><br /></p>

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