Mfr. of sailing masts from blank sheet - has material folded round tapered mandrel with edges of sheet held by series of screws

摘要

Manufacture of sailing masts from a blank (15) of sheet metal starts with a mandrel (22) being pressed down by a screw (31) onto the sheet, which rests on a hollowed wooden base (24). This forms the blank into a 'U' section, and the screw is then removed. For the next stage a long screw (38) is inserted through previously drilled holes at the top of the 'U' section and formers (36) and nuts (39). As the nuts are tightened the 'U' section is closed cover the mandrel. The screws are removed and the mandrel which like the must is tapered, is withdrawn. The excess flanges (43, 43') are then cut off to leave the completed mast.