Method of making key for opening food tin - uses lengthwise oblique cut in stem followed by splitting stem and twisting half stem sideways

摘要

The process is used to fabricate a key which opens a food tin by winding a strip out of the wall of the tin. A longitudinal slanted cut (3) is made in a piece of metal wire (1), a cutting-stamping tool then being used to split the wire by twisting a half of the wire (4) laterally over a pre-determined length. Finally the twisted half is re-positioned on the wire axis (x-x) defining a narrow crevice (5) into which the tongue of a tin is introduced. The crevice may reduce in width uniformly from its inlet to its bottom (5a).