What happened to the 0.01g electronic scales?

[Rabid Rabbit]

About a year ago I put on my wish list a electronic scale that is accurate to 0.01gr. Every company had at least one, but now I can't fine any. What happened?

 

[Third_Rail]

Maybe they weren't as accurate as hoped?

 

[molonlabe]

A lot of electronic scales tend to be temperature sensitive and the compensation gets a little expensive. That is one of the reasons I still uses my beam balance. They probably as the previous person said could not meet their own spec.

 

[pcf]

If you can stand that dirty french metric system, you can get a laboratory scale that will measure to .001g (that's .003grs). Ohaus scales come to mind but the people I borrowed it from wanted $500 or their scale back. Precision balances are okay, but they are frustrating to use, the scales are sensitive to moving air (breathing, air conditioning, doors opening and closing, etc). Better served with a analytical balance (the scales in plexiglass housing), but they run in the $1000 plus range.

 

[Rabid Rabbit]

Yeah, that is what I was thinking too. I'm looking to speed up my bullet sorting and load development time and was really looking forward to getting that accuracy, heck I'd be happy with one and a half digit accuracy. I guess I'll have to settle for one digit accuracy.

 

[The Bushmaster]

Sorry Rabid Rabbit. But I don't believe that they (the reloading industry) ever made a 0.01+/- scale. Someone outside the reloading industry may have, but....

 

[Coltdriver]

If you keep your eye out over on ebay you will occasionally come across an old scientific scale that will go to that level. They used to cost a lot of money but are up against much cheaper competition now.

I sold a Fischer Scientific last year that was calibrated to .01 grains and it only brought about $130.

It originally sold for nearly $1000!

 

[cracked butt]

When you get a balance that sensitive, you will run into problems with air flow unless the balance has a closable housing over it. You also need a very sturdy bench, we have very sturdy laboratory benches where I work, but if you were to lean on a countertop while trying to read a scale that goes to 2 places, it will throw off the measurement. We actually have solid granite countertops with solid granite legs (the whole setup weighs 500+ lbs) for mounting balances that weigh beyond 2 places.

 

[Bob41081]

Balance

Take a look at www.coleparmer.com. They have balance that will do .01 g for less than $500. I'm not sure if they will sell to individuals because of all the drug laws, but it's worth a look/try. I agree with the commets about air currents and weight tables.

Bob

 

[BobC]

If you intend to weigh the powder charge for each individual cartridge, then the following technique won't help, but it may be helpful for setting up "production line" assemblies.

Assuming that the powder measure is throwing consistent charges and you want a more accurate reading: throw a double charge into the scale pan and divide the weight by 2.

For example, for a 7.0 grain desired charge (and a scale that displays weight to .1 grain):
a single charge reading of 7.0 grains indicates the weight is somewhere between 6.95 and 7.05 grains.
But a double charge with a reading of 14.0, indicates a combined weight of 13.95 to 14.05 grains (or a single charge of 6.975 to 7.025 grain). The uncertainty in the weight is half that of the first measurement.

Obviously, averaging even more charges in this way will result in a more precise estimate of the weight. But, we must consider the overall system. If the powder dispenser has a repeatability error of .05 grain from throw to throw, then measuring the powder weight to .01 grain does not improve the our prediction of the weight of the next charge to be thrown.