Weighing in on Egg Scales

Early egg scales helped small farmers grade and market eggs.


| May 2011



This version of the Acme was introduced at the Chicago World’s Fair in 1933-34

This version of the Acme was introduced at the Chicago World’s Fair in 1933-34.

My experience with egg scales started when I was a child on our farm in South Dakota. I had the responsibility of collecting, washing and weighing eggs. Today, the first question people ask when they see my egg scale collection is why eggs are weighed. People usually haven’t considered how the eggs they purchased were classified. As a boy, I weighed and cleaned eggs to increase the price of a dozen eggs by a few cents as I placed them in 30 dozen cases to be sold to grocery stores and egg processors. 

Grading of eggs by weight began about 1900 as a way of selecting the ideal size egg for hatching purposes. Early “egg graders” were preset to select eggs of a certain weight.  During World War I, the U.S. War Department bought eggs in large quantities and paid for them on the basis of size, which was determined by weight. Since poultry farmers were paid a premium for graded eggs, i.e., eggs that were sorted by size, World War I created an immediate market for “egg scales.” Farmers graded eggs to sell to retailers as a source of cash, thus perpetuating the need for egg scales. World War II created the greatest single demand for egg scales as the U.S. War Department bought eggs in huge quantities to feed the troops overseas. Most egg scales were invented and manufactured between 1920 and 1940.

A Specialty product

Acme egg grading scales were produced by Specialty Mfg. Co., St. Paul, Minn., founded by William Boss in 1900. Specialty’s first products included a grass catcher for a lawn mower, clothesline reel and garden hose reel followed by several other items, including the Acme egg grading scale. In 1922, Acme inventor N.E. Chapman filed for a patent for what he referred to as an egg grading device. The patent was granted in June 1924.

Still in operation today, Specialty manufactures numerous products for various industries. The company chairperson is Heidi Sandberg McKeown, great-granddaughter of the company’s founder.

Fins tell weight

Early Acme egg scales were of aluminum construction. Later models have tin bases that tended to rust over time. The scales work on the weight-lifting principle. Each scale has nine fins that are lifted to determine an egg’s weight. The weight of the egg lifts individual fins that rise until the precise weight of the egg is determined.

The egg cup on the 1924 patent for the Acme scale is generally oval like an egg and is parallel to the scale. However, the cup on some scales is positioned at right angles to the scale. Those models were probably produced after 1933. The egg cups are attached with aluminum rivets or with two slots cut in the cup and an aluminum strip holding the cup in place. The weight shown on the scale is the calculated weight per dozen, not the weight of one egg.