Calibrating a Postal Scale

[wcs94]

Lincoln cents from 1982 to date weigh about 2.5 grams.

from

3rd paragraph

[Abe]

There's a set of new calibration weights on Ebay for a buy it now price of 20.00. Looks like an excellent deal.

(and no, I'm not the one selling them)

[thrugoodmarshall]

I don't know how your scale can be adjusted (2-point; single point...), but I believe a nickel masses 5.000g...

Hmmm...here's the specs...

Beachcomber wrote:

[Beachcomber]

I believe my postal scale is reading a bit high...

Does anyone know an easy way of calibrating it, say with coins or some other standard system of weights measure?

Beachcomber

[Kathy]

high...

say with coins or some

weigh it empty and set zero

[zxcvbob]

Is your scale convertible to grams? A US Jefferson nickel weighs exactly 5 grams.

And I think 25 dimes weighs exactly 2 ounces.

Hope this helps, Bob

[Richard J Kinch]

Say you confirm the scale is off. Whaddya gonna do about it? It doesn't have any calibration adjustments or enough resolution to calculate a compensation.

[Goedjn]

If only you knew how much an ounce of water weighed....

[David Martel]

Beach,

penny: 2.509 grams nickel: 4.995 grams dime: 2.263 grams quarter: 5.706 grams

Dave M.

[Jeff Wisnia]

At what temperature?

Jeff

[Richard J Kinch]

You assume the error is linear, repeatable, and no hysteresis. Typically not the case. Compounded by digitization error.

[George E. Cawthon]

You can use shot. Depends on the size as to how many make an ounce, but any gun store should be able to tell you. But I like the idea of coins. Any book on coin collecting will tell the size and weight of coins.

[George E. Cawthon]

Gees, Richard, you are suppose to be an engineer. Adjust it with a paper clip, make a mark, etc.

[jtnospam]

Years ago, I took a scale down to the regional office of the U.S. Bureau of Standards, and they calibrated my scale for a five dollar fee, with a dated calibration stamp. I understand that state and county "weights and measures" will provide a similar service for a fee. For some businesses, such as produce departments of supermarkets, and gas stations, periodic calibration is mandatory. -Jitney

[Beachcomber]

Thanks for all the good suggestions. I used the 20 nickles is about

100 g. reference and converted to ounces. (1 kg = 2.2 lb 16 oz = 1 lb).

As it turns out, the postal meter reads high, but just by a fraction of an ounce. I wonder if they construct it that way on purpose to "round up" the purchase of postage to the next oz, maybe to compensate for inaccuracies in other meters.

Beachcomber

[George E. Cawthon]

Wow! You're right I never thought about hysteresis or digitization error.

I didn't assume anything, but apparently you assumed it was an electronic scale. Apparently you never heard of standard weights and interpolation.

Course the easiest solution for weighing light objects is a yard stick with a hole to hang it in the center, and strings to hold the weighed object and a known weight.

But I admit I'm a mess, I don't even consider parallax when I eat with a fork.

[clifto]

Watch that. Real old (pre-1982?) pennies were three grams. Recent pennies I've measured at two grams. But yes, between the two periods they were

2.5 grams.