Digital Scale and Accuracy

[Trickymissfit]

In your response you are now using the words "extremely close" and "pretty much the same". Also you end with: "You check everything critical off of three measuring devices and you calibrate off of three devices. If one is differing then something's wrong."

That's all well and good, but with that statement you're saying you were still using the expensive primary Lab scales for your final okay before things went out the door aren't you? If not, why have the Lab and it's precision equipment if that cheaper stuff on the floor was so great? IMHO the answer is that the shop equipment wasn't good enough for a final okay to ship and that's basically what I'm trying to say in regards to the use of cheap digitals in powder weighing when you equate them with a good beam scale during final trickling of the powder to get to your target weight. My guess is that a lot of these cheap digitals people are buying aren't nearly as good as a beam scale. I know my buddy bought a Cabelas digital and the first time we went to use it we found it would not hold zero and it's repeatability was horrible. It went back and he bought a Dillon beam scale.

first of all I use a U.S. built scale, and have owned four of them in the past and present. I tend to avoid Chinese stuff like the plague. I can readilly see that your unfamilure with the process for doing inspections or you'd know that it's done in a redundent way. Things do get out of spec, and you must catch it before it goes out the door. It wasn't just weights and measures, but every part manufactured was checked completely in stages. Lastly I'll put my digital scales up against any beam scale you can lay your hands on. Your preaching into the wind, and nobody's listening
gary

 

[Topgun 30-06]

Again well and good, but you didn't answer my question! Did you or did you not rely on the more expensive Lab equipment to ensure that your cheaper stuff out on the floor was functioning well enough to allow products to leave the plant within specs? Did you use the Lab equipment to final check 1 for 1, 1 for 10, 1 for 100 or whatever other number before products were shipped? I find it amazing that you are making your statement about my knowledge when you know nothing of what I did. FYI one major part of my job was to ensure that company equipment in the food establishments within the nine county area I covered were not only functioning properly and accurately within specs for that particular instrument, but also that they were of proper design for their use. Those firms ranged from small Ma & Pa shops to multimillion dollar plants run by the biggest firms in the world! Therefore I think I know more than just a little bit about what we're discussing in this thread. You keep your digitals and we'll keep our balance beams for what we're talking about and we'll all live happily ever after!

 

[Truc]

I use a Tanita electronic digital scale, even 1 lonely Kernel can change the reading by .05 gr. Cost was around $200 at the time probably 6 yrs ago and still using the same battery

 

[Max Heat]

I use a Tanita electronic digital scale, even 1 lonely Kernel can change the reading by .05 gr. Cost was around $200 at the time probably 6 yrs ago and still using the same battery

Hmm, that's interesting - you must be using some pretty heavy (dense) powder. I have found that a single granule (stick) of powder (RL-19) typically weighs in at between about .02 and .03gr, depending in it's length, as there IS some length variation in the sticks.

I have it figured at about 40 granules/grain averaged out, which is 2X what your numbers imply. They must be really big granules.

 

[Trickymissfit]

I use a Tanita electronic digital scale, even 1 lonely Kernel can change the reading by .05 gr. Cost was around $200 at the time probably 6 yrs ago and still using the same battery

I don't know that I've ever seen one of them.
gary

 

[Topgun 30-06]

I've never heard of them either, but you need to remember that in a digital scale the sensitivity of the device is critical and that depends on the breaking point where the scale decides to register an increase as powder is trickled onto the pan. That is why I prefer a moving beam scale because you can see the device moving up to the horizontal postion that your charge weight is set for as the powder is trickled into the pan. You don't have that luxury with the digital scales we're talking about where all of a sudden you are at the charge weight, as well as possibly being under or over depending on the sensitivity of the scale being used. That's where expensive Lab scales would be handy and the cheaper ones being sold to reloaders can't match them.

 

[Truc]

The model I have is Tanita Model 1210 here is the link if they are measuring precious gems like diamonds in carrots it has to be accurate

1210N Professional Diamond Scale

 

[Trickymissfit]

The model I have is Tanita Model 1210 here is the link if they are measuring precious gems like diamonds in carrots it has to be accurate

1210N Professional Diamond Scale

only thing I saw that I didn't like about it was that it was limited to 308 grains, and even then I never go that high in weight. But some of the guys that do really big stuff might find that it comes up short a slight bit. I seldom weight bullets anymore
gary

 

[Truc]

I guess a 308 gr Diamond is rare
I never weigh bullets, only powder and occasionally brass

 

[Shootin4fun]

I seached for this thread because I also bought a relatively inexpensive scale ~50 at Cabellas and wanted to see if anyone actually identifies a scale with a certain level of a) accuracy, and b) consistency.

I saw inconsistencies and historisis (doesn't move, then goes too far) in the scale I bought and agree that it is good for weighing brass and non super critical things, but not powder charges. Like others here I've been working in analog and digital electronics for over 30 years in builiding these kinds of things, and understand the difficulty in producing an analog-> digital device that has the level of precision we want in reloading. I assume most manufacturers use a transducer, but I think the only way to really be accurate is to use an internal balance beam and laser to measure the diplacement.

HERE'S WHAT I WOULD SET AS A MANDATORY CRITERIA BECAUSE MY GOOD OLD RCBS GRAIN SCALE CAN DO IT: CONSISTENTLY TELL THE DIFFERENCE WHEN I DROP 1 KERNEL OF VARGET IN THE PAN. MY CHARGES OR +/- 1 KERNEL.

Now, I don't know what that weighs but I'm going to guess that a scale with +/- .01 grains conisistency from load to load would meet this level of senstivity. The absolute accuracy, (that is how close it is to the actual weight can be a much looser tolerancy) I would guess +/- .1 grains. I have never seen variation in of .2 grains affect a load's accuracy. If 36.0 gr is the best load, 36.2 will probably be just as good, as long as that whole batch was loaded the same.

A quick settle down time, insensitivity to air currents, and ease of reading (digits, no parallax as with lining up the beam pointer with the center line) is what would motivate me to use a digital scale. But without a high degree of accuracy and consistency, I don't want to take the chance of spoiling everything else I've done to keep things right up to that point.

 

[Mike 338]

RCBS matches up with beam scale. If it throws a little extra, it indicates such and is fast to correct. It seems to measure down to 2-3 kernels of extruded powder and very accurate for ball. That's good enough for me but I'm not a perfectionist. I don't see using a beam scale again unless there's a power failure.

 

[Joe King]

I have the Pact II measure and scale combo. it doesn't replace my beam scale for precision, but for loads that I'm not so concerned about being just so it's great(where MOA is good enough). let it do it's thing while you seat a bullet in the previous case, that's a time saver. and the scale being a separate unit from the measure is great for weight sorting bullets and cases. I do not ever ever use it with loads that are at or close to max though. A beam killer like they called me when they first came out, not so much it's just another tool that has a useful function.

 

[TracySes23]

Digital measuring equipment of any kind always has built in inaccuracy. If it reads in .1 increments, it can possibly be in the unknown area inbetween increments and it could be off as much as .09 either way before it trips over to the next number. That gives it the potential inaccuracy of .18. Only if the device reads in .01 increments can you depend on .1 accuracy. I've proved this concept to a number of people over the years since digital micrometers and indicators came out.
For these reasons I never trust digital anything to be as accurate as the smallest increment on the instrument.
I have seen a few instruments that will display a + or - to indicate if you're off on either side, but you still don't know exactly how much you're off.
A beam scale can also be off, but if it's pivot points are sharp & clean, it should always be reliable.
From personal experience, I've discovered you can read a beam scale while it's still swinging after it's settled down some. It will swing very close to plus and minus equally on both sides of zero. It does however take a bit of practice to be consistent. If you have doubts about how well you can do this, simply allow it to completely to settle down and check your progress as to how well you doing. I read this in a gun magazine over 30 years ago.
You can also learn to use your finger to make it settle down faster. This works well, but also takes practice. However I have discovered that with proper powders and the right chamber size in a good powder measure, you can depend on measured loads within .1 grain. This has been especially true for me with pistol powders, from Bullseye up through 2400 & 4227. I've never used ball powders, but I've been told most of these measure very accurately through powder measures. I've also never used any powder slower than Dupont 4320.
My powder measure is an Ohaus DU-O Measure. It has a small chamber for pistol powders and a large chamber for a larger charge of slower burning rifle powders. Maybe some of the newer measures have this dual chamber capability. I know I love my powder measure. I bought it in the late 60's or early 70's.

 

[Trickymissfit]

Digital measuring equipment of any kind always has built in inaccuracy. If it reads in .1 increments, it can possibly be in the unknown area inbetween increments and it could be off as much as .09 either way before it trips over to the next number. That gives it the potential inaccuracy of .18. Only if the device reads in .01 increments can you depend on .1 accuracy. I've proved this concept to a number of people over the years since digital micrometers and indicators came out.
For these reasons I never trust digital anything to be as accurate as the smallest increment on the instrument.
I have seen a few instruments that will display a + or - to indicate if you're off on either side, but you still don't know exactly how much you're off.
A beam scale can also be off, but if it's pivot points are sharp & clean, it should always be reliable.
From personal experience, I've discovered you can read a beam scale while it's still swinging after it's settled down some. It will swing very close to plus and minus equally on both sides of zero. It does however take a bit of practice to be consistent. If you have doubts about how well you can do this, simply allow it to completely to settle down and check your progress as to how well you doing. I read this in a gun magazine over 30 years ago.
You can also learn to use your finger to make it settle down faster. This works well, but also takes practice. However I have discovered that with proper powders and the right chamber size in a good powder measure, you can depend on measured loads within .1 grain. This has been especially true for me with pistol powders, from Bullseye up through 2400 & 4227. I've never used ball powders, but I've been told most of these measure very accurately through powder measures. I've also never used any powder slower than Dupont 4320.
My powder measure is an Ohaus DU-O Measure. It has a small chamber for pistol powders and a large chamber for a larger charge of slower burning rifle powders. Maybe some of the newer measures have this dual chamber capability. I know I love my powder measure. I bought it in the late 60' or early 70's.

one more time for the masses! Nobody in this country that does precision weight measuring uses a beam scale anymore. All balancing equipment made in the last 20 years is digital. The calibration weights are done on digital scales similar to what you just knocked. I'd also imagine that the quality check on your beam scale was done off a digital scale. Those beam scales went to the Dixie Dumpster in 2000 (that's where I got two Ohaus 304's)

My trusty olf Lyman #55 will throw ball powders within a .25 grain window all day long (that's +/-.125 grain), and my Harrell will always put ball powder in the +/-.1 grain area. The nice thing about the Harrell is that I can get my log book out and dial in the clicks, and start right up from where I left off the last time I used that load. It will be right there everytime.

gary