Electronic scales question

[Pulp]

I've had a Cabela's scale for several years, and always have been a bit skeptical of it. Seems I'm always having to tare it after weighing something. The other day I weighted a batch of .45-70 cast bullets to throw out the off weight ones. After each bullet, was removed the scale would nearly always go back to 0.2 and I'd have to tare it. So I'm always wondering, is the error on the bullet, or on the empty pan. In this case 0.2 grains is only a 0.04% error, so I'm not too concerned about that. But say 6 grains of TiteGroup in a 9mm. Now it's a 3.3% error, which could be important if loading max loads. 6 grains is a bit below max, but a 0.2 grain error would make it max.
So am I worrying about nothing, and just keep hitting the tare button?

 

[dennishoddy]

You shouldn’t have to rezero after weighing a load.
Digital scales are cheap. I’d replace it.

 

[alank2]

It is part of the technology of the scale. All digital scales use a load sensor to weigh and to give you a weight, they are essentially comparing two load sensor values against each other. When you hit tare/zero, it might be that "11453" is zero. Then you put a bullet on it and the sensor becomes "11489" and the scale does the math between the difference and converts it to a proper weight. The problem with the load sensor is that you can't always count on "11453" being zero. They wander for various reasons, voltage fluctuations, temperature fluctuations, etc. Their software usually will correct it when "on zero"; for example, if it goes from 11453 to 11454 to 11455, then 11455 will automatically become the new "zero". But things change when a weight is on the scale. It then knows it is off zero, but that doesn't stop the sensor from wandering. So the longer you stay off zero with something on the scale, the more likely when you remove the weight, it may not be back at zero. If you have a battery power option, give it a try, it may be more stable than a wall adapter/plugged in thing. Or it may not, if it is getting older, it could just be a function of aging.

 

[Rustygun]

I went through a few scales with the same questions. even bought the Dillon $130 version & found even this expensive option was unable to show the same results twice. Went back to the old RCBS balance beam for a while but it required much more time and squinting to get readings.

Finally got a $20 scale from Amazon called a Brifit. Been using it for about three years and am very happy with it. I can weigh a powder charge, lift it off the scale and put it back on and get exactly the same reading. It is sensitive enough that if there is even a small amount of air movement the scale will not provide consistent readings. I have occasionally built a three sided cardboard shelter around the scale if I need to run a fan or the a/c.

 

[Beau]

I have the Hornady auto measure. And I've found that it needs to be turned on and started running,but I let it hold that weight for about an hour before I start. It will eventually get back to zero and pour a second time. After the hour has passed I pour it back in the hopper and zero the pan. Stays accurate only after it's allowed to warm up for awhile.

 

[Rez Exelon]

I've got two scales that I use that I've calibrated between them. Scale "A" is my primary, and is a $20 Amazon special. Scale "B" is another $20 Amazon special that I think I paid 4 bucks for at a bin store. I know that the reading on "B" is going to be something like +.2gr compared to "A" but that reading is consistent. Point being that if "A" goes down, I just adjust the math using "B" to get the exact same load.

Now, for both scales I have a couple of "known weights". These are the calibration weights, as well as various casings that I've weighed on multiple scales to know their value. I just check against them from time to time.

Either way, as long as your trust whatever your "scale A" is then just accept that it's your default gold standard weight. And if you use another, then you have to calibrate between them to know how to "shift" the numbers.