Calibrating a Postal Scale

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

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:

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

high...

say with coins or some

weigh it empty and set zero

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

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.

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

Beach,

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

Dave M.

At what temperature?

Jeff

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

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.

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

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

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

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

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.

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