powder scale problems

jbcricket · September 12, 2013, 02:46 PM

I'm sitting down at my table about to load up some 338 rums and i've got both a rcbs 5-0-5 beam scale and an old rcbs digital scale that came with the electronic powder dispenser i bought probably 15 years ago, they had an infrared beam that went between the dispenser and the scale and they worked together when placed next to each other so the beam could read back and forth, the dispenser eventually quit working but the scale still works so i've been using it with my 5-0-5 scale and its served me reasonably well for a while. The two scales have never really been in total agreement but have always been close enough to be in the ballpark. Today they seem to be consistently reading different from each other by almost a grain. The question is which one is most likely to be reading wrong. Both scales are around the same age, probably 15 years old or so. Has anyone else dealt with this issue?

Misssissippi Dave · September 12, 2013, 03:34 PM

Using some check weights will probably be the best way to tell. If you don't have any, maybe another reloader in your area does.

**Unclenick** · September 12, 2013, 04:34 PM

Jbcricket,

If you are describing what I think you are, the older RCBS dispenser with the scale to the right side of the dispenser and not the more modern one with the scale plugged into the front of the dispenser, it was made for RCBS by PACT on an OEM basis. If that's the one you have, it should come with two check weights: a 20 grams (308.65 grains) and 50 grams (771.62 grains). They should both be accurate within 0.1 grains and should be able to be used to check either scale. You can also use Sierra MatchKing bullets as check weights as they are usually within 0.1 grain of the weight claimed on the box.

It's very hard to make gravity unequal on the two sides of a balance's knife edge, so unless you have a mechanical problem with the 505, it's more likely to be correct. Do check that no iron filings have got into the damper magnets to drag against the flat conducting plate that slides between them. Check for that and for knife edge cleanliness and condition by weighing something, then gently lifting the pointer and releasing it to see where it settles, and then gently depressing it down and releasing it to see where it settles. If the two settling spots are within 0.1 grain of each other at the pointer, then it's likely working fine.

On the electronic scale, if you have the one made by PACT, you can view their calibrating directions using the two weights on line and follow them to see if that corrects it. If not, it could likely be repaired or you could replace it with a better one.

Brian Enos sells a German-made scale with a lifetime warranty and a battery powered smaller one with a 20 year warranty. Neither is as inexpensive as some of the scales you can get at Amazon, but cheap scales are catch as catch can on performance and drift. Enos's scales are both designed to work for reloading and things you might neglect to check out on cheap ones are already verified with them, like accepting trickling without shutting off in the middle of taking a weight, or the the 0.1 grain decimal place not skipping some digits because of conversion rounding from metric units, as some scales will do.

boondocker385 · September 13, 2013, 12:13 AM

On you 5-0-5 also check for debris on the pan and the pan holder.

wncchester · September 13, 2013, 01:54 PM

Obviously the beam scale's parts have to be clean but it's accuracy will last forever unless you damage it. No eletronic device is going to do that; when was the last time you had a computer crash, or cell phone, GPS, etc. to quit?

I used to be an electonic measurement equipment calibration/repair tech in the space program; there are no electonic gimmicks on my reloading bench. And there won't be unless someone gives me one!

jbcricket · September 14, 2013, 03:35 PM

Thanks for the suggestions, i took the 20 gm calibration weight that came with the digital scale and i weighed it first on the digital, it weighed in at a fraction over 20 gms, then i hit the grams to grains conversion button, cant remember what the exact number was but i then weighed it on my 5-0-5 and it was quite a ways off. I took the weight in the kitchen and put it on my wifes food scale and it weighed right at 20 grams. I'm guessing maybe something happened to the 5-0-5 or it got dirty. I will check it out as soon as i get the chance. Unclenik, your are right about the digital scale, it was exactly the same as the pact version. It was not very good in my experience.

September 12, 2013, 02:46 PM	#1
jbcricket Member Join Date: April 28, 2009 Location: idaho Posts: 85	powder scale problems I'm sitting down at my table about to load up some 338 rums and i've got both a rcbs 5-0-5 beam scale and an old rcbs digital scale that came with the electronic powder dispenser i bought probably 15 years ago, they had an infrared beam that went between the dispenser and the scale and they worked together when placed next to each other so the beam could read back and forth, the dispenser eventually quit working but the scale still works so i've been using it with my 5-0-5 scale and its served me reasonably well for a while. The two scales have never really been in total agreement but have always been close enough to be in the ballpark. Today they seem to be consistently reading different from each other by almost a grain. The question is which one is most likely to be reading wrong. Both scales are around the same age, probably 15 years old or so. Has anyone else dealt with this issue?

September 12, 2013, 04:34 PM	#3
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,061	Jbcricket, If you are describing what I think you are, the older RCBS dispenser with the scale to the right side of the dispenser and not the more modern one with the scale plugged into the front of the dispenser, it was made for RCBS by PACT on an OEM basis. If that's the one you have, it should come with two check weights: a 20 grams (308.65 grains) and 50 grams (771.62 grains). They should both be accurate within 0.1 grains and should be able to be used to check either scale. You can also use Sierra MatchKing bullets as check weights as they are usually within 0.1 grain of the weight claimed on the box. It's very hard to make gravity unequal on the two sides of a balance's knife edge, so unless you have a mechanical problem with the 505, it's more likely to be correct. Do check that no iron filings have got into the damper magnets to drag against the flat conducting plate that slides between them. Check for that and for knife edge cleanliness and condition by weighing something, then gently lifting the pointer and releasing it to see where it settles, and then gently depressing it down and releasing it to see where it settles. If the two settling spots are within 0.1 grain of each other at the pointer, then it's likely working fine. On the electronic scale, if you have the one made by PACT, you can view their calibrating directions using the two weights on line and follow them to see if that corrects it. If not, it could likely be repaired or you could replace it with a better one. Brian Enos sells a German-made scale with a lifetime warranty and a battery powered smaller one with a 20 year warranty. Neither is as inexpensive as some of the scales you can get at Amazon, but cheap scales are catch as catch can on performance and drift. Enos's scales are both designed to work for reloading and things you might neglect to check out on cheap ones are already verified with them, like accepting trickling without shutting off in the middle of taking a weight, or the the 0.1 grain decimal place not skipping some digits because of conversion rounding from metric units, as some scales will do. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle Last edited by Unclenick; September 12, 2013 at 04:40 PM.

September 12, 2013, 03:34 PM	#2
Misssissippi Dave Senior Member Join Date: December 5, 2009 Posts: 1,411	Using some check weights will probably be the best way to tell. If you don't have any, maybe another reloader in your area does.

September 13, 2013, 12:13 AM	#4
boondocker385 Senior Member Join Date: March 6, 2013 Posts: 640	On you 5-0-5 also check for debris on the pan and the pan holder.

September 13, 2013, 01:54 PM	#5
wncchester Senior Member Join Date: December 1, 2002 Posts: 2,832	Obviously the beam scale's parts have to be clean but it's accuracy will last forever unless you damage it. No eletronic device is going to do that; when was the last time you had a computer crash, or cell phone, GPS, etc. to quit? I used to be an electonic measurement equipment calibration/repair tech in the space program; there are no electonic gimmicks on my reloading bench. And there won't be unless someone gives me one!

September 14, 2013, 03:35 PM	#6
jbcricket Member Join Date: April 28, 2009 Location: idaho Posts: 85	Thanks for the suggestions, i took the 20 gm calibration weight that came with the digital scale and i weighed it first on the digital, it weighed in at a fraction over 20 gms, then i hit the grams to grains conversion button, cant remember what the exact number was but i then weighed it on my 5-0-5 and it was quite a ways off. I took the weight in the kitchen and put it on my wifes food scale and it weighed right at 20 grams. I'm guessing maybe something happened to the 5-0-5 or it got dirty. I will check it out as soon as i get the chance. Unclenik, your are right about the digital scale, it was exactly the same as the pact version. It was not very good in my experience.