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The making of an embossed die for printing our en-velope stamps closely resembles the process we havedescribed for the making of a steel-engraved printingplate. The process differs only slightly and then onlyin technique. The engraver, as before, cuts the designonto a steel die. In this case the die is the end of asteel shaft. After the die has been made and approved,
The O'Connell Envelope-making machine being dem-onstrated at an International Philatelic Exhibition inNew York. it is hardened and now is placed directly against a some-what larger steel shaft. Under very great pressure thehard die is forced directly against the softer steel "hub."As a considerable amount of steel has to be displacedthe process requires several applications of the die tothe hub. Between each application some of the displacedmetal is removed from the hub. When the die has beensunk into the hub to its required depth, the hub is hard-ened and now, by reversing the process, is capable ofstriking off as many working dies as may be required. |
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