Rivet head dating
They are used to join thin sheets of material together.
A metallic pin with a head, used for uniting two plates or pieces of material together, by passing it through them and then beating or pressing down the point so that it shall spread out and form a second head; a pin or bolt headed or clinched at both ends. Before being installed a rivet consists of a smooth cylindrical shaft with a head on one end. On installation the rivet is placed in a punched or drilled hole, and the tail is upset, or bucked (i.e., deformed), so that it expands to about 1.5 times the original shaft diameter, holding the rivet in place.
The setting of these fasteners requires access to both sides of a structure.The rivet is placed in a hole drilled through both pieces of material, and its end beaten into a dome.A tool called a rivet set or a rivet snap is used to to finish the joint. Pop rivets are used where there is only access to one side of the work.Hundreds of thousands of solid rivets are used to assemble the frame of a modern aircraft.Such rivets come with rounded (universal) or 100° countersunk heads.
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The filler metals used in brazing must have a lower melting point than that of the material being joined. Soldering is a type of brazing which works at lower temperatures.