Is 2 grams enough?

The new dollar coins are being issued, this time with portraits of the Presidents, done four per year. The New York Times reports the details here (free registration required).

Using the Presidential portraits for the coins is a good idea, and may lead to better public acceptance of the dollar coin--had federal officials taken this approach instead of first promoting Susan B. Anthony and then Sacagawea, they may have had more success. Still better would have been to do the Presidents in reverse chronology, therefore starting with Reagan (only dead Presidents will be honored). They would have had a lot of trouble keeping up with demand for a Reagan dollar, I suspect, but he's now at the end of the line.

But the fundamental problem remains, and its an obvious one, the new dollar is far too easily confused with a quarter. It's not the consumer's fault, a quarter weighs 6 grams, the new dollar 8 grams, an almost imperceptible difference (for reference, an ounce is 28.3 grams). Though humans have a hard time telling the difference, it's enough for vending machines to distinguish, and the investment that owners of vending machines made to retool for the Sacagawea dollar was given as the reason why the Presidential dollars couldn't be upsized to a more appropriate weight, say double the quarter.

According to the Times, the financials behind printing dollar bills are more complicated that you might think, so there hasn't been a rush to retire Washington's paper portraits.