Type metal

Metal letters is the designation of a lead alloy for casting movable type printing types.

In graphic arts until the 1970s lead types were common. The printing processes are now largely converted to eg offset method.

The metal letters in the stricter sense was composed of lead and 5-6 % tin and 28 to 29% antimony together, sometimes a little copper. Traces of zinc, arsenic, aluminum, nickel and iron were limited to 0.01 to 0.05%.

The main component lead is the "stuff" ( old name for letters metal) the switch and formability, antimony the necessary hardness, the tin makes for a good connection of the individual metals and a corresponding toughness and abrasion resistance. Copper increases the hardness and resistance of Scripture.

In addition, other alloys were in use for each particular case of type casting:

• Hintergiessmetall ( lead, tin, 2.5-3.5 % antimony 3.5 to 4.5 %)
• Typo ( graph ) metal ( lead, tin, 2.5-3.5 % antimony 11.5 to 12.5 %) for the blank material on Typograph - setting machines
• Lino (type) metal ( lead, tin, 4.5-5.5 % antimony 11.5 to 12.5 %) for Linotype typesetting machines
• Mono (type) metal ( lead, tin, 8.5-9.5 % antimony 18.5M and 19.5M %) for Monotype casting machines
• Sheet metal ( lead, tin 15.5 to 16 %, antimony 4-5 %) for music engraving plates.
• Regulations tablets metal
• Excluding metal
• Stereotypiemetall
• And many more

The variety of alloys can be explained by the special requirements: Single types for hand composition were used repeatedly and therefore had to be resistant. For the lead- generator set optimized casting machines could be operated properly with the exactly matched to these alloys.

Zinc interferes with, for example, the flow behavior and by forming an oxide film forming, copper crystals can clog the Gießmund at too high a concentration. By burning and dross formation, the concentration ratios change in operation in the melt, so this filler metal ( also defined composition ) is compensated.

• Alloy
• Rate ( pressure)
• Lead