Digital Scale -Odd Fluctuations

[peeplwtchr]

Hi All-

So I am precision loading for a ladder test. I use both a beam and a digital, which in the past has been VERY consistent and accurate. When I compared my digital readings from yesterday to the beam, everything I weighed on the digital reads lower on the beam.

I assume something was interfereing with the digital? I researched what might cause this, but saw nothing of what my suspicions might be. Do you see any possible causes in my environment?

1. I am 3 feet from an electrical outlet
2. Within 10 feet, there is a tv, amazon fire stick, cell phone
3. Ambient temp is 78 degrees
4. The scale and table are stable
5. Both scales zeroed and calibrated
6. Powder is CFE-223

Thanks!

 

[kcofohio]

Intermittent air flow?

 

[forty_caliber]

How long has it been since you cleaned the pivot points on the beam scale? How long did you let the digital scale warm up for?

What is the make and model of both scales? This will help get better answers.

.40

.

 

[peeplwtchr]

How long has it been since you cleaned the pivot points on the beam scale? How long did you let the digital scale warm up for?

What is the make and model of both scales? This will help get better answers.

.40

.

-5 min. warmup
-Never cleaned pivot points, after 20 hours of use
- Digital- Bald Eagle
- Beam - RCBS M500

 

[Riomouse911]

Batteries?

stay safe.

 

[peeplwtchr]

Intermittent air flow?

Yes, AC vent directly above, 7 feet over

 

[peeplwtchr]

Batteries?

stay safe.

No, I am using plug

 

[peeplwtchr]

Batteries?

stay safe.

Thanks, why I check with 2 scales for rifle.

 

[AJC1]

The most important question is what do they say compared to your test standards.

Warmup on my chargemaster is 30 minutes then I calibrate and verify with a 20 grain standard. I use the 20 because I load a lot of 223 and that is close to most loads.

 

[peeplwtchr]

This is interesting. I turned the tv off, moved my laptop and cell phone away, and now the digital reads much closer to the beam.

 

[forty_caliber]

I think most digital scales want about 1/2 hour to warm up. Might be worthwhile to check the manual about your specific model. I wipe the pivot knives and point down with an alcohol pad before each use. Just takes a second and will help keep it running true.

.40

 

[peeplwtchr]

Thx, will do both. Manual says let warm up 5 min, but I'm in no hurry. I turned the AC on, getting 2 hundredths of drift on an empty scale, this spot must be too close to the vents.

 

[jmorris]

This is interesting. I turned the tv off, moved my laptop and cell phone away, and now the digital reads much closer to the beam.

How far apart were they before and after?

 

[peeplwtchr]

How far apart were they before and after?

TV/Firestick - 9 feet
Laptop/phone - 3 feet

 

[Riomouse911]

Our houses have plenty of possible interference sources, I think you may have found a couple right there. I keep my tv remote, cell and wireless phone and other electronic things on the bench across the garage and keep fans from blowing near me when I’m loading using my digital scale for these same reasons.

I recall people saying fluorescent lights may also cause interference. I don’t know if that’s true or not but I guess it could be. I don’t have any lights near me, all my garage lighting is led and it’s mounted up on the ten foot ceiling.

Hopefully you’ve found the culprit .

Stay safe.

 

[DukeConnor]

What do your check weights tell you ?

 

[peeplwtchr]

I think most digital scales want about 1/2 hour to warm up. Might be worthwhile to check the manual about your specific model. I wipe the pivot knives and point down with an alcohol pad before each use. Just takes a second and will help keep it running true.

.40

I wiped the pivot rods, it moves more freely now, thanks! I wonder if silicon spray on the rods would help too?

EDIT- Oh yes, the beam trickles like a dream now.

 

[forty_caliber]

I wiped the pivot rods, it moves more freely now, thanks! I wonder if silicon spray on the rods would help too?

EDIT- Oh yes, the beam trickles like a dream now.

No lube. No nothing. Just clean and dry is the best.

.40

 

[LiveLife]

why I check with 2 scales

We have stated many times that using two scales cannot be trusted.

Verify the scale(s) with a set of check weights.

For me, a reliable reloading scale should have the resolution of .1 gr and be repeatable, especially at the powder charge range being used.

It's too bad that most "reloading" check weights only go down to .5 gr to not allow checking sensitivity of .1 gr resolution but there are check weights you can buy that are affordable enough like this set for $15 - https://www.amazon.com/American-Wei...coding=UTF8&psc=1&refRID=VW7SHP1YDXZ1WNA5J5SE

Here's another for $12 - https://www.amazon.com/Bekith-Preci...CCPQJCJ7AKA&psc=1&refRID=2JHSM8R5XCCPQJCJ7AKA

I use Ohaus ASTM Class 6 check weights that include 1 mg check weight (.015 gr) - https://www.zoro.com/kbmt/calibration-weight-set/

 

[Todd NE WY]

What do your check weights tell you ?

You have to make sure they are reading the same before you start measuring powder, doesn't have to be a check weight but an object that is weighed in each to verify they read the same. They may have been that far off yesterday if you weighed on the digital. Using scales to verify each other works but you have to "calibrate" them to each other.

 

[peeplwtchr]

I wiped the pivot rods, it moves more freely now, thanks!

We have stated many times that using two scales cannot be trusted.

Verify the scale(s) with a set of check weights.

For me, a reliable reloading scale should have the resolution of .1 gr and be repeatable, especially at the powder charge range being used.

It's too bad that most "reloading" check weights only go down to .5 gr to not allow checking sensitivity of .1 gr resolution but there are check weights you can buy that are affordable enough like this set for $15 - https://www.amazon.com/American-Wei...coding=UTF8&psc=1&refRID=VW7SHP1YDXZ1WNA5J5SE

Here's another for $12 - https://www.amazon.com/Bekith-Preci...CCPQJCJ7AKA&psc=1&refRID=2JHSM8R5XCCPQJCJ7AKA

I use Ohaus ASTM Class 6 check weights that include 1 mg check weight (.015 gr) - https://www.zoro.com/kbmt/calibration-weight-set/

Purchased. The ones I looked at previously didn't have a wider range for cross checking.

Thanks

 

[LiveLife]

Verify the scale(s) with a set of check weights.

Purchased

Then use the scale that consistently verifies check weights in the powder charge range you are using.

 

[Mr. Zorg]

I purchased my reloading scale calibration weights from eBay. In addition to the sets sold by RCBS & Lyman, a search for "apothecary scale weights" will turn up sets in grains, scruples, and drams with some in great condition and others in so-so condition. Weights below 10 grains will be classified as Fractional Weights and will typically range from 5 grains to 0.5 grains.

1 scruple = 20 grains
1 dram = 3 scruples = 60 grains

Some sets will have both calibration weights in that system and calibration weights in grams and milligrams included in the same set.

 

[peeplwtchr]

Our houses have plenty of possible interference sources, I think you may have found a couple right there. I keep my tv remote, cell and wireless phone and other electronic things on the bench across the garage and keep fans from blowing near me when I’m loading using my digital scale for these same reasons.

I recall people saying fluorescent lights may also cause interference. I don’t know if that’s true or not but I guess it could be. I don’t have any lights near me, all my garage lighting is led and it’s mounted up on the ten foot ceiling.

Hopefully you’ve found the culprit .

Stay safe.

I just bought LEDs for what will be my reloading room (Storage garage).

 

[denton]

A few years ago, I wrote up some test results for electronic vs. balance scales. Quick summary:

The balance scale I tested was very robust. It worked consistently whether cold or hot, and through being disassembled and re-assembled.

The electronic scale was a real "houseplant". It was very temperature sensitive and very susceptible to radio frequency interference via the power cord. That's simply cheap design. A decent design won't behave that way.