Calibration weights (any cheap alternatives) - Page 2

F. Guffey · February 11, 2015, 09:33 AM

50 Grams = 771.61792 Grains

http://www.asknumbers.com/GramsToGrains.aspx

http://www.midwayusa.com/product/415...grain-capacity

RCBS Model 1010 Magnetic Powder Scale 1010 Grain Capacity

I have Ohaus 3 and 4 beam scales, when weighing 4 different 50 gram check weights I get 4 different readings on one scale. One of the check weights could be correct, I could trim the weights to match, problem and question, how would I validate? I believe the scales are correct.

Again, I have two identical sets of check weight, I use one or the other.

F. Guffey

Bart B. · February 11, 2015, 04:21 PM

Send the check weights in question to a NIST certified metrology lab with precision measuring and weighing stuff traceable to ISO standards. They'll tell you their exact weight to several decimal places. Something every machine shop guru knows how to do.

There's a Texas state metrology lab in Giddings, TX.

https://www.texasagriculture.gov/Reg...rologyLab.aspx

FrankenMauser · February 12, 2015, 12:28 AM

Quote:

50 Grams = 771.61792 Grains

Yep.

My balance beams top out at 510 gr, and the electronic scale doesn't get used for powder, so it doesn't matter much (2,500 gr capacity - has two 50 gr calibration/check weights).

**Unclenick** · February 12, 2015, 01:25 PM

Be wary of using coins. The published tolerances are mint. When the state quarters were coming out, a friend collected them new from the bank. I think she'd just got Utah, because my Excel file is for Utah quarters. The result was:

Utah Quarter, Phildelphia mint, 35 samples in mint condition (weights in grains).
87.68 Mean
1.96 Extreme Spread; 2.24%
0.4507 S.D.
88.70 High
86.74 Low

All within Frankenmauser's listed range. I also had six from the Denver mint that were in her jar, but that's too few to tell much from. Their weights were inside the Philadelphia mint's range, so I doubt they were significantly different. All were the same year, but I forgot to record that for some reason.

Obviously, once you start to look at worn coins, it's another whole ball game. Comparing a heavy new coin to a well worn light coin can, obviously, give you a bigger difference.

In any event, a two grain spread is not very tight scale calibration unless you know that it's a scaling error and not an offset error. If it's an offset error, it could cause real problems with pistol loads. Here, again, my solution is to take the coin to the pharmacist and have it weighed so you know what it is. Probably won't cost you a dime.

February 11, 2015, 04:21 PM	#27
Bart B. Senior Member Join Date: February 15, 2009 Posts: 8,927	Send the check weights in question to a NIST certified metrology lab with precision measuring and weighing stuff traceable to ISO standards. They'll tell you their exact weight to several decimal places. Something every machine shop guru knows how to do. There's a Texas state metrology lab in Giddings, TX. https://www.texasagriculture.gov/Reg...rologyLab.aspx Last edited by Bart B.; February 11, 2015 at 05:56 PM.

February 12, 2015, 01:25 PM	#29
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,061	Be wary of using coins. The published tolerances are mint. When the state quarters were coming out, a friend collected them new from the bank. I think she'd just got Utah, because my Excel file is for Utah quarters. The result was: Utah Quarter, Phildelphia mint, 35 samples in mint condition (weights in grains). 87.68 Mean 1.96 Extreme Spread; 2.24% 0.4507 S.D. 88.70 High 86.74 Low All within Frankenmauser's listed range. I also had six from the Denver mint that were in her jar, but that's too few to tell much from. Their weights were inside the Philadelphia mint's range, so I doubt they were significantly different. All were the same year, but I forgot to record that for some reason. Obviously, once you start to look at worn coins, it's another whole ball game. Comparing a heavy new coin to a well worn light coin can, obviously, give you a bigger difference. In any event, a two grain spread is not very tight scale calibration unless you know that it's a scaling error and not an offset error. If it's an offset error, it could cause real problems with pistol loads. Here, again, my solution is to take the coin to the pharmacist and have it weighed so you know what it is. Probably won't cost you a dime. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

February 11, 2015, 09:33 AM	#26
F. Guffey Senior Member Join Date: July 18, 2008 Posts: 7,249	50 Grams = 771.61792 Grains http://www.asknumbers.com/GramsToGrains.aspx http://www.midwayusa.com/product/415...grain-capacity RCBS Model 1010 Magnetic Powder Scale 1010 Grain Capacity I have Ohaus 3 and 4 beam scales, when weighing 4 different 50 gram check weights I get 4 different readings on one scale. One of the check weights could be correct, I could trim the weights to match, problem and question, how would I validate? I believe the scales are correct. Again, I have two identical sets of check weight, I use one or the other. F. Guffey