boo radley Posted March 16, 2007 Share Posted March 16, 2007 I've gotten concerned about my old 505 balance scale, because I recently started using Clays, and it seems I can crank on the powder adjustment screw all day, and not see much difference. Unfortunately, I don't have any check-weights. Should probably buy some, but in the meantime, I'm wondering if a US nickel, which is supposed to be 5.0 grams, is close enough for a sanity check? Link to comment Share on other sites More sharing options...
Canuck-IL Posted March 16, 2007 Share Posted March 16, 2007 (edited) I thought the composition, and probably the weight, of coinage has changed over the years. I'd use the powder holder from the scale as the standard and have a couple of friends weigh it on theirs. /Bryan Edited March 16, 2007 by Canuck-IL Link to comment Share on other sites More sharing options...
kmca Posted March 16, 2007 Share Posted March 16, 2007 Do you have a friendly pharmacist that will weigh a nickel for you? Link to comment Share on other sites More sharing options...
Chris Keen Posted March 16, 2007 Share Posted March 16, 2007 Why not weigh a bullet ??? 115 grains (give or take 1 grain) is almost always 115 grains. Weigh it on a friends scale (digital hopefully) and then write that number down. Write it on the bullet if possible, and then ALWAYS KEEP IT WITH YOUR SCALE and call that your check weight. Link to comment Share on other sites More sharing options...
Duane Thomas Posted March 16, 2007 Share Posted March 16, 2007 Now that's just too easy. Link to comment Share on other sites More sharing options...
Chris Keen Posted March 16, 2007 Share Posted March 16, 2007 I thought so Sometimes the simplest answers are the last ones thought of. Link to comment Share on other sites More sharing options...
BSeevers Posted March 17, 2007 Share Posted March 17, 2007 (edited) I thought it was an 8-ball? LE please ingore. I have a bullet that is 114.6 gr that I know is consistant since I keep it in my scale pouch and I have used it for years to "check" my calibrations. Edited March 17, 2007 by BSeevers Link to comment Share on other sites More sharing options...
Chris Keen Posted March 17, 2007 Share Posted March 17, 2007 Wonder where I got that great idea from ................... ??? Link to comment Share on other sites More sharing options...
KentG Posted March 17, 2007 Share Posted March 17, 2007 I have to wonder how close you can calibrate a scale using a 115 gr bullet when you intend to measure about 5 gr. That is if your just going to use it for pistol weight charges. I actually use 2 RCBS scales located in a closet in my relaoding room/spare bedroom and I have the set of weights I got from midway or someone way back. The set goes from .5gr to around 50 I think but I only use the small ones to check out a 5 gr setting. I set both scales to measure what I settle at and cross check them. I would like to find a true set of calibrated weights that didnt have to come from a lab supply source and cost a ton. But it really isnt THAT important, what counts is your chrony readings and consistant throws from the press. If the scale shows the charge you settle on is consistant thats what REALLY counts in my book. Link to comment Share on other sites More sharing options...
North Posted March 17, 2007 Share Posted March 17, 2007 (edited) Tell you what, I'll weigh a few nickles for on monday and report back. Heck a penny will be closer to what you need. However there are 453.ish grams per pound and 7000 grains. you need something as a standard that weighs 5 grains or 1/3 grams to use. I will experiment on monday report back. Edited March 17, 2007 by North Link to comment Share on other sites More sharing options...
Chris Keen Posted March 17, 2007 Share Posted March 17, 2007 I have a digital RCBS scale with 2 check weights. They tell you to use the smaller one for calibration if you generally load small amounts of powder. I don't know why but my SMALL check weight is 100 grams = 308 grains. Nowhere near the 3.3 grains I load for Prod. Link to comment Share on other sites More sharing options...
boo radley Posted March 17, 2007 Author Share Posted March 17, 2007 Thx all -- Chris, I did think about using a bullet, but wasn't sure how accurate the advertised weights were, and wanted something a little lighter....But on your suggestion, weight a Zero 180gr, and it came out 179.9, so I figured screw it, and loaded up 500 rounds of .45acp using Clays. If it's hot, it's hot. <g> I think I will get a friend, in medical research, to weight a nickel or dime or something, and use that as a gold standard. Link to comment Share on other sites More sharing options...
KentG Posted March 17, 2007 Share Posted March 17, 2007 Thx all -- Chris, I did think about using a bullet, but wasn't sure how accurate the advertised weights were, and wanted something a little lighter....But on your suggestion, weight a Zero 180gr, and it came out 179.9, so I figured screw it, and loaded up 500 rounds of .45acp using Clays.If it's hot, it's hot. <g> I think I will get a friend, in medical research, to weight a nickel or dime or something, and use that as a gold standard. Without trying it I wonder if a large paper clip is closer to the weight you want. Link to comment Share on other sites More sharing options...
BSeevers Posted March 17, 2007 Share Posted March 17, 2007 (edited) You don't just use "a nickle" or "a bullet" but the Exact Same Bullet. I have the exact same bullet and if it weighs 114.6 in 1990 then its a great confidence check that my scale says 114.6 in 2007. Yea my calibration weights are 300+ grains so I don't think you need a lighter weight to check it, but yes using the same paper clip would be a great test too. Your scale could be .1 or .2 off of a $10K fancy one but as long as its consistant and you chrono, who cares. Repeatability and consistancy is the goal. Edited March 17, 2007 by BSeevers Link to comment Share on other sites More sharing options...
CenTX Posted March 17, 2007 Share Posted March 17, 2007 I calibrated my Pact electronic scale and then used a Lyman check weight to test it. With the 10 grain test weight it was dead on. With two 20 grain test weights it showed 39.9. A bright shiny penny, 2006 D, is 38.7 grains. A bright shiny dime, 2005 D, is 35.4 grains. Link to comment Share on other sites More sharing options...
Chris Keen Posted March 17, 2007 Share Posted March 17, 2007 What if they're not bright & shiny ??? Link to comment Share on other sites More sharing options...
North Posted March 18, 2007 Share Posted March 18, 2007 What if they're not bright & shiny ??? add .03 grains for every shade of dullness. Link to comment Share on other sites More sharing options...
Bronson7 Posted March 21, 2007 Share Posted March 21, 2007 This is my take on it and I'm pretty anal about accuracy. Weighing something on a friends scale and then transferring it to yours also transfers his inaccuracy. Scales do not have the same inaccuracy/accuracy over their entire range. The best way, imho, is to calibrate your scale for what you are measuring. In other words, don't check it at 100 grains, when you want to measure 5 grains. This is best served by using check weights, that way, you actually cal for the charge you're using. In the interim, ask your friendly local pharmacist to weigh a paper clip. His scales, I would suspect, are very accurate, but by all means, get the check weights at the earliest opportunity. Bronson7 Link to comment Share on other sites More sharing options...
bpowe Posted March 25, 2007 Share Posted March 25, 2007 Don't worry too much about the absolute accuracy of the balance. The balance is calculating the difference between the powder holder (tare weight) and the powder holder + powder. The inaccuracy of each weight is mostly canceled out. This is why even on very accurate laboratory balances, they weigh samples by difference. Bill Link to comment Share on other sites More sharing options...
Bronson7 Posted March 25, 2007 Share Posted March 25, 2007 Don't worry too much about the absolute accuracy of the balance. The balance is calculating the difference between the powder holder (tare weight) and the powder holder + powder. The inaccuracy of each weight is mostly canceled out. This is why even on very accurate laboratory balances, they weigh samples by difference.Bill Bill, you lost me on that one. Can you explain in a bit more detail with an example? Thanks. Bronson Link to comment Share on other sites More sharing options...
George Posted March 26, 2007 Share Posted March 26, 2007 Repeatability is way more important that actual weight accuracy. Who cares if the charge you are throwing is actually 5.1 grains versus 5.25. Heck most powders don't even respond much to less than 2 tenths charge weight variance and I really don't know of a scale available for a reasonable price that can resolve less than a tenth of a grain +- anyway. As long as what your scale thinks is 5.4 grains is still saying it's 5.4 grains a year from now you are good to go. In other words, if that scale still weighs some specific object with the same result today as it did back when, then it's still OK. Here is my take on this kinda' stuff from another thread on a similar vein here: http://www.brianenos.com/forums/index.php?...c=46425&hl= Link to comment Share on other sites More sharing options...
bpowe Posted March 26, 2007 Share Posted March 26, 2007 (edited) Pretty simple actually. Balances are inherently pretty precise instruments, just not necessarily accurate. If it is not calibrated, it will give you a weight that is off by some amount, every time (it IS precise, just not accurate). So the tare weight is actual weight +/- some error. To minimize the problem, balances use a "tare weight" for example, the powder holder. The weight of the powder holder is calculated by the electronics and then subtracted, the display now shows "0.0". When you add powder the electronics is actually seeing the total weight, powder + pan but only displaying the powder weight. The way this helps accuracy is like this... (powder + pan +/- error) - (pan +/- error) = powder weight since the balance is pretty precise, the (+/- error) cancels out to give a more accurate weight. Hope this helps Bill George, a beam balance, as long as the knife edge and fulcrum are in good shape, is more likely to be accurate than an electronic one, it doesn't have the built in inaccuracies of the load cell. But it still needs some expertise to produce accuracy! Edited March 26, 2007 by bpowe Link to comment Share on other sites More sharing options...
George Posted March 26, 2007 Share Posted March 26, 2007 BTW, what Bruce is saying is the reason why throwing a number of charges into a single pan then dividing the final weight by the number of charges weighed is the best way to get a solid measure of what charge weight you are really throwing (on average). This averages the error of both the measure and the scale out for you, win, win! Link to comment Share on other sites More sharing options...
AlamoShooter Posted March 26, 2007 Share Posted March 26, 2007 Is your scale set up away from the AC/ Heater vent? I found even with my scale 10 feet way from the vent it would efect the scale. Link to comment Share on other sites More sharing options...
benos Posted March 30, 2007 Share Posted March 30, 2007 I can't remember ever calibrating my scale. (Okay maybe I did once or twice but it was never anything I cared about.) The most important thing was the velocity I wanted. The charge weight was just a reference to get back to the velocity. So as long as the scale zeroed out about 15 minutes after turning it on, or was within .01 of a grain or so, I didn't think about it any more. be Link to comment Share on other sites More sharing options...
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