What successive operations shall the shipbuilders carry out to join steel plates and thus create a ship’s hull that is also watertight?
In the first section we look at what tools the shipbuilder uses for this and in the second part we analyse the successive operations.
Dolly / bucking bar:The dolly is a heavy solid metal bar that is held by the dolly holder to keep the head in position while the person operating the hammer swages the buck-tail of the rivet. One end of the dolly has a dome. The head of the rivet fits into this dome. There is a different type of dolly for each type of rivet head.
Hammer: The hammer is used to flatten the buck-tail of the rivet.
Tongs: The tongs are used to pick up the hot rivet from the forge or from the electric rivet heater.
Rivet heater: An electric rivet heater is used in the example. The rivets can also be brought to temperature in a permanent or mobile forge. Ovens are now used to heat the rivets.
Rivets: There are various shapes, thicknesses and lengths of rivets to suite their application. The example uses rivets with a rounded head and a round buck-tail with a cross-section of 13 mm.
The steel plates have to be subjected to a number of operations before they can be riveted. For example, the plates first have to be provided with corresponding holes into which the rivets fit. The holes may be countersunk (using a countersink drill), into which the swaged metal disappears. Two steel plates with corresponding pre-drilled holes.
Preparing the steel plate is the subject of another skill.
The rivet is placed in the electric rivet heater until the buck-tail of the rivet is white-hot.
The tongs are used to push the hot rivet through the corresponding holes in the steel plates.The dolly holder uses the tongs to bring the hot rivet to the hole in the steel plates. (image 1)
The dolly holder holds the rivet in place using the dolly while the riveter flattens the buck-tail of the rivet with heavy blows. (image 2)
Using heavy blows, the riveter flattens the buck-tail of the still hot rivet. (image 3)
The two steel plates have now been joined (image 4). For special joints that are subjected to extreme forces or at locations where damage is likely several rows of rivets are placed next to each other.