First, I'd suggest reading this piece that covers typewriter type terminology. That's a mouthful, but it's important to have everyone understand and use the same terms in order to communicate.
Now, a bit of history....
|Type slug from Harris Visible No. 4.|
TYPEWRITER TYPE SOURCES
For much of the history of manufacturing typewriters in the United States, it appears as if all the big manufacturers actually made their own type in either their own plants or plants captive to them. The companies began to employ special designers as time went on to develop more and more interesting kinds of type styles to be offered, but still kept all of the manufacturing in house.
It was not until after the Second World War that US manufacturers began heavily to purchase type manufactured elsewhere for application to typewriters otherwise wholly built in the United States. The earliest known example of this was when, in 1955, R. C. Allen began to apply type imported from Germany which had been made by Ransmayer and Rodrian, Berlin. From that time on, other US makers began to employ foreign made type in some or other quantity; of course, many also began to import to the US portable (and later standard) typewriters made overseas which were themselves, naturally, fitted with foreign-made type.
MANUFACTURING OF TYPE
PRINT - The Magazine of the Graphic Arts - included in its Typewriter Type issue (June, 1952) a description of the manufacture of type slugs at the Remington-Rand plant in Elmira, New York. In order to avoid plagiarism we will simply describe the process in our own words.
According to PRINT, typewriter type was originally cast (or 'moulded') as had been done with the type used in printing presses. However, this process by itself didn't produce a type face that could withstand years of hard use. We don't have a good handle on the exact date that it occurred but according to PRINT, makers changed over to die forging soft slugs which were then hardened to withstand the abuse of hard service.
The material used for the slugs in the example given in PRINT was "soft, low carbon steel" which was received at the plant in 20 foot lengths and then cut into slugs. Actually, the slugs were cut and stamped at the same time with "wings" or tabs that were then folded to form the slot on the back of the slug that would match up with the type bar after the slug was fully complete.
Next, the slug was placed into a press which contained a die that had sunk into its face the desired type style. Pressing the die against the slug with 11 tons of force caused the slug to conform to the die and produced the raised "type face" or lettering that would eventually make the impression on a completed typewriter; the actual mechanical action of this special machine was not just direct pressure but also a rolling or, as described, a "kneading" action in order to ensure complete formation of the raised characters. Flash or excess from the die molding process was trimmed at this time.
At this point the type slug looks complete but is far too soft for actual service. Use of a soft material allowed easier cutting and forming, but a series of hardening steps was now required to prepare the type slugs for millions of impacts in actual service. The first step was immersion in a bath of cyanide at 1600 F; following removal from this bath the slugs were quenched. These steps hardened the slugs. Next, when cool, the slugs were lowered into a cadmium plating bath that was intended to provide the proper hardening specifically on the type face (the characters, that is) itself. Each was inspected after having been removed from the plating.
Alignment of the type slug was critical in every direction and dimension, and companies developed various jigs and procedures to ensure the type slugs were applied properly. Some sort of alignment check was of course also required after the machine was assembled, and at that point the manufacturing life of the type slug is completed when the adjuster/inspector signs off on the machine and a signed or stamped type proof sheet is produced. (These can sometimes be found with a typewriter; they were often shipped with the machine new.)
It should be added that some rebuilders applied new type to machines as a matter of habit, in order to restore the machine to fully like-new characteristics. These companies then had to at least have the ability to get slugs from the OEM and then also the ability to properly apply, align and inspect the slugs / machine thereafter.
Type slugs can be removed and resoldered; the most common reason for that these days is looseness or breakage but an increasing interest is being seen in converting QWERTY machines to QWERTZ or back, particularly for enthusiasts acquiring machines not regularly sold in their home countries. For example, an American collector might acquire a QWERTZ Princess portable if he or she was fairly confident a local shop could swap two type slugs and two keytops to convert the machine to English QWERTY layout. Naturally, other conversions are possible such as AZERTY, and so forth.
We hope this brief description has been of some assistance to collectors, historians and even those vaguely contemplating making new parts or machines. The type (and type bars) are of course a critical part of a typewriter and require a very high degree of precision. According to Beeching:
"There are approximately forty-two operations in the manufacture of each type bar alone. From this it can be deduced that typewriter production is a manufacturing nightmare. It is quite true to say that today, with any given quantity of capital, manufacturing capacity and skill, almost anything is more profitable to manufacture than a typewriter." (Wilfred A. Beeching, "Century of the Typewriter.")
When Beeching originally wrote that in 1973 (in the first edition) he certainly was correct, although it must be pointed out that people did still need typewriters and that good ones would sell. Today, we might consider 3D printing as a possible or less expensive way to manufacture type slugs but the questions of accuracy and hardness would need serious investigation with this new method. In fact, the type slugs might be the most questionable part of all if 3D printing were considered for new use.