1. Evidence

In his memoir, written by 1874 but not published in a reliable edition until 1981 as History of Typefounding in the United States { {Bruce 1874/1981}, David Bruce, Jr. says:

"As remarked before, Mr. White's total ignorance of even the present system of type founding led him into an error which in turn has been of great importance to the art. Hence the method using hardened & tempered molds was by him thought essential, & as an American method has ever since been adopted throughout all the foundries. In England, Germany, & France the custom was to use unhardened type molds. Edwin Starr has the name of being the first introducer of hardened molds. Edwin was a frank communicative man upon all the details & improvements as they developed themselves & as he travelled about itinerating from one foundry to another as a Superior workman & received high wages, as a matter of course - without reserve he spread his own improvements along with the others - broadcast." [italics in the original] (pp. 55-56)

The occasion of White's "total ignorance" was his desire to enter into the business of type founding without any prior knowledge of the field. This led him, in an incident well-known to the history of American type founding, to send Starr as an industrial spy into the works of Binny and Ronaldson. Starr's tenure there was brief, and he returned to White to help establish White's Type Foundry. Whether Starr did not realize that the type hand molds he saw at Binny & Ronaldson were unhardened (and assumed that they were so) or whether Starr or White simply felt that molds should be hardened is not entirely clear.

(See {Annenberg 1994} for a discussion of this incident.)

2. Argument

One of the most distinctive features of the first type casting machine, the "pivotal" type caster of David Bruce, Jr., is the way in which the mold is mounted on a pivoting frame in order to contact the nozzle of the metal melting pot only when the actual cast occurs. Similar complexities occur on later casting machines, as well (e.g., the Linotype).

There are probably three reasons for this complexity. First, the pivotal type caster is in essence a mechanized hand mold. It is no doubt easer to open its mold and discharge the cast type with the mold clear of the nozzle. Second, the mold must be cooler than the pot and nozzle in order for the type to solidify. Bruce in the 1830s and 1840s did not yet have water-cooling, so pivoting the mold away helped to maintain its temperature.

(Aside: Some later pivotal type casters did have water-cooled molds. The Nuernberger-Rettig is an example of this. Also, the Ludlow Typograph (a linecaster) both moved its melting pot away from its mold and had a water-cooled mold.)

I wish to argue that there was a third reason for this. The only tool steels available to Bruce were conventional high-carbon steels. The range at which these steels are tempered - that is, begin to soften - run from about 350 to 700 degrees Fahrenheit. The range of temperatures for casting types runs around 650 to 730 degrees. A mold without water cooling which is held in close contact with a 730 degree or so pot for an extended period of time will soften beyond the desirable range of hardness.

So I argue that in part - not wholly, but in part - Starr's limited espionage and White's ignorance led not only to better hand molds in America but also to the distinctive form of the pivotal type caster.

3. References

{Annenberg 1994} Annenberg, Maurice. Ed. Stephen O. Saxe. Type Foundries of America and their Catalogs. Second Edition, 1994. New Castle, DE: Oak Knoll Press, 1994.

{Bruce 1874/1981} Bruce, David, Jr. History of Typefounding in the United States. Ed. James Eckman. (NY: The Typophiles, 1981).