Air Mail Accuracy letter scale

Air Mail Accuracy letter scale

This letter scale has several marks. At the front and at the back a sticker shows the name of the model and the name of the maker. At the side, the name of the manufacturer TRINER SCALE & MFG.CO CHICAGO,ILL. is stamped into the surface, also PATENTS PENDING and the number 9 in a circle. These texts are separately painted white. Remarkably, this American letter scale doesn't have the postal rates. It's an unequal-arm scale. The weighing is basically the comparison of weights, is it lighter or heavier than x oz. The range is 9 oz. The slidable weight can be moved in steps of half an ounce, from one groove to another groove. Zero leveling of this letter scale is done by turning a screw in the long beam. Several slightly different designs of this exceptionally solid letter scale exist.

slidable weight and grooves at scale beam

exactly balanced

zero leveling

For instance specimens with at the side the text: PROPERTY OF U.S.P.O. DEPT. and -almost always- a year. U.S.P.O. DEP.T is short for United States Postal Office Department. The dates I have seen are: 1940, '41, '43, '44, '45, '46, '50, '51, '53, '54, '56, and '65. Scales from the years 1938 and 1939 have a brass colored plate and beam. Specimens of 1931 and 1932 possess a cylindrical slidable weight. Predecessors have a free, not closed in, beam and a frame that looks like half. These scales date for example from 1921 and 1932. Triner also made a model with the name Air Mail scale. It strongly resembles the Air Mail Accuracy. More recent specimens have a model number (AA-1, 88, en 93). The youngest designs have a more simple frame base. The Accuracy exists in the colors light grey, dark blue, black, gold colored and army green. The base has two bore-holes to facilitate fastening. Other specimens have a range of 16 oz. (1 Lbs) or even a range upto 4 Lbs. Below some more photos of this letter scale and of related specimens.

extremely solid	name of model	beam and weight are chromed
readable at both sides	text at side	bottom with 2 holes
predecessor with free beam	predecessor with a cylindrical weight + frame-closed beam	U.S.P.T.O. 1939
specimen with postal rates	similar model	sticker of the similar model
brass colored plate 1951	1940	more simple frame base