American Telephone and Telegraph Company, American Telephone and Telegraph Company. Information Dept · (New York, American Telephone and Telegraph Co., etc.) · leaf 164
of hard ruhher.Not infrequently, during the assem-bling process, metal chips would bepicked up which would short-circuitthe insulation. The injection moldingof plastic material for insulation ofthe plug parts eliminated this diffi-culty and produced a plug with betterand more stable insulation.… … The hot pre-forms are dropped into the dies, the press closes, and in three minutes seven new hand telephones emerge 134 Bell Telephone Magazine AUTUMN In hand. It has been difficult to age and improve the stability of thecure heavy sections of phenol plastic casting, about 40 percent silica is…
Telephone
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