Scale Accuracy

[Wilburt]

All this talk about digital scales has me wondering. I see onein my future i hope... Anyway I got courious to just how acurate my 505 was after all the moving i've done. I bought a set of RCBS check weights. I don't know what's concidered "normal or acceptable". Here are the results:

10gr check weight:
Scale setting: 10/0/0
Reading: too heavy

Scale setting: 0/9/9
Reading: ~9.01

20gr check weight:
Scale setting: 20/0/0
Reading: ~20.02

Scale setting: 10/9/9
Reading: ~19.92

 

[Bronson7]

Uh, Wilbert, how are you measuring hundredths of a grain?
Bronson7

 

[Griz44]

You mean everyone doesn't weigh each flake of powder individually? How can you get a balanced load from one side of the case to the other if you don't?

(Don't sweat the hundredths)

 

[Wilburt]

I fully understand about hundreths. No i can't measure it but i was guesstimating b/c it wasn't "dead-nuts" (machinist term). The reason i asked is it's closer to the 9 than the 0.

 

[Bronson7]

Ah, Ok. Had me going there for a moment
Bronson7

 

[ranger335v]

Well, digital scales won't give you those tiny increments to be concerned with, they aren't sensitive enough to even attempt to read to that resolution.

 

[jwr_747]

read a report a while back on digital vs. balance beam scales. don't remember where but the bottom line was both varied in actual vs. displayed weight. actual may be 10gr. but read 9.5gr. the surprise was the balance beam was more consistant.if you loaded 10 rounds,you might have 10 different weights using digital where using the beam scale you may only have 4 different weights. the digital was more accurate on displayed weight,but the beam scale was more consistant on weight indicated. jwr

 

[Wilburt]

digital scales won't give you those tiny increments

I know but i still want one.

 

[ranger335v]

"Quote: digital scales won't give you those tiny increments I know but i still want one."

Ah. Then go for it. That's all the justification most folks seem to have for digital scales or calipers anyway and it's sufficent.

 

[The Bushmaster]

I've been reloading for the last 22 years. With that said...When I bought my digital electronic scale about 19 years ago (RCBS Powder Pro) I noted that if you were wanting a charge of 5.6 grains of a given powder there was a "light" 5.6 and a "heavy" 5.6. Dummy me called RCBS and asked if they were ever going to manufacture and sell a powder scale that would give weights in tenths and hundreds. All I heard on the other end before they hung up was laughter.

If you are in the mid range of a powder charge or near the top end and you are getting +/- .2 grain difference you will be O K and as accurate as anyone out there...

 

[Bitswap]

Interesting...

I have always thought a 'cheap' mechanical scale was more accurate than and electronic scale. It's not prone to deviations caused by floresent lights(?) and temperature changes. It appears previous posts confirm this. I don't have a super-accurate electronic scale so it may be better.

As an electronics buff, I know things change when electronics heat up or cool down. Sability is perimount when using these things, like turning of the heat/AC units which will screw up the mechanical with air currents.

Electronic scales use a piezo sensor to detect weight. Caliberating and zeroing is necessary, but on a good day, expect +/- 0.1 grain accuracy. Same accuracy you can expect from a mechanical balance beam. Your load accuracty should be able to tollerate that deviation.

My best electronic scale is built into my powder dispensor. When settled down and warmed up, it is spot on, consistent and only requires zeroing every 10 rounds whether it needs it or not. When you get to know your manual scale, you can easily see if your off by a few tenths. My electronics are always backed up with my mechanical. I've found plugging in my powder dispensor 24 hours before using has always yeilded excellent results, over kill I know, but it works for me.

I have a cheap ($90) electronic scale that I use to weigh cases and categorize them. Definatly beats the mechanical here for ease of use.

 

[Wilburt]

All I heard on the other end before they hung up was laughter.

Funny

 

[The Bushmaster]

Bitswap...My 19 year old RCBS Powder Pro will weigh that 5.6 grains, mentioned above and repeat it when I lift the pan off and put it back on. My RCBS 5-0-5 will do the same...They are accurate within that "light" or "heavy" 5.6...(Or any other weight for that matter)...I use the electronic because it is soo much faster then the balance beam...I have not had any problems with floresent lights either and I have one about 3 1/2 feet from the digital scale. The only problems I have with either is when my wife walks by and both will move then (mini earthquake)...

 

[Bitswap]

Bush: no arguements here. I concur that electronic scales are accurate. I was pointing out some of the things that could cause them to be 'off'.

I haven't noticed florescents affecting my scales either, but was in my manual, just being on the safe side.

But it is nice to know if your in a remote location without electrcity that the manual scale in on par with the electronics be it a lot harder to use but better than nothing.

The wife and kids walking buy is a testiment to how sensitive these things are. When you think about it, 0.1 grain is nothing! Literally (70,000's of a pound).

Any scale is better than no scale. I've never used a powder dipper ever and never will.

 

[loplop]

Bitswap, I'm a bit of an audiophile. I found, long ago, that anything with transitors sounded better when left on 24/7. The only hifi equipment I don't leave on all the time is tubes.

I leave my scale on 24/7, too (the plug-in one).

My cheap Hornady GS-1500 scale that came in my LNL Classic Kit (battery power only) starts to read differently as it "warms" up. Since it times out rather quickly, I just measure within the first 2 minutes and it's pretty repeatable and accurate. It gets less accurate (or, shall I say, starts to drift) if I leave it on until it "sleeps."

If I ever get really nutty about measuring accuracy, I'll run a dedicated circuit to my scale. I did this to my hifi...

I'll stop now

 

[D. Manley]

There are some very high precision electronic scales to be had such as, THIS ONE with an advertised 0.02 grain accuracy for $189.95. There are others with even more precision (for even more money) as well. That said, IMO I have doubts that kind of precision is required or even useful to most reloaders who use automatic powder measures. Unless trickling/weighing individual charges, 0.1 grain accuracy is "good enough". I do think any electronic's accuracy should be regularly validated by a good balance beam, though.

For my purposes, I only weigh a single throw every now and again during a session for confirmation of my settings. When setting up (Dillon) I throw a few to "settle" the powder and adjust to get close to my desired charge. From then on I throw 10 charges into the pan and weigh continuing adjusting until the 10 throws are my target weight x 10. After getting a couple of precise 10-throw weights that are spot-on, you can pretty well bet that your individual charges are about as close to target weight as your PM system is capable of.

 

[dalepres]

I fully understand about hundreths. No i can't measure it but i was guesstimating b/c it wasn't "dead-nuts" (machinist term). The reason i asked is it's closer to the 9 than the 0.

It's called interpolating: 3: to estimate values of (data or a function) between two known values

 

[joneb]

And if you are loading outdoors which one would you rather have

 

[The Bushmaster]

Jibjab...Even my 5-0-5 moves around in even the slightest breeze. So what's yer point. Outside? Must be a bench rester...

 

[Wilburt]

It's called interpolating: 3: to estimate values of (data or a function) between two known values

English never was my stong suit One more word to the 'ol vocabulary

 

[Bitswap]

And if you are loading outdoors which one would you rather have

That's a real good question. My portable electronic will timeout when powered by batteries. Both are affected by wind.

I've been using a mechanical with a u-shaped cardboard wind break. If the wind picks up, even this doesn't work.

I'd be interested to see how others do it outside for some ideas.

 

[CBS220]

I know but i still want one.

That's what I said.

Then I got one, and after a little while I went right back to the beam balance.

Don't sweat the hundreths, or even a few tenths unless you're pushing absolutely max loads.

 

[snuffy]

Interesting thread!

My 12 YO RCBS powder pro has worked flawlessly for all those years. It seldom needs calibrating, because the Lyman check weights I have alway read the same each time I turn it on. If it's weighing them the same as their known value, why should I calibrate it? I turn it on to warm it up, when I start sizing cases for a batch of shells. By the time I'm ready to charge them, it has warmed up and stabilized to hold zero.

As others have said, 0.1, or on tenth of a grain is all the sensitivity, we as handloaders, need. Most benchresters charge cases by volume once they have a grain weight value that works.

 

[CatsEye]

I had wondered about the accuracy of my little Lee balance scale so I tested it. I didn't have a certified weight so I improvised. In the quality lab at work I weighed a small paper clip to be .428 grams. I calculated this to be 6.6 grains. I balanced my scale to zero then set the scale to 6.6 and dropped the paper clip in the cup. I got a perfect reading. Since it is a balance scale I knew that it should be accurate, but it was nice to know for sure.

 

[dalepres]

I can understand wanting the ease of use of an electronic but the reliability and availability of a balance beam scale seems to have more advantages. If I were going to have an electronic scale, I'd still have a balance beam. I don't like electronics or batteries nearly as much as I like mechanical reliability - and I spent years working in electronics .