At a central location near the areas being riveted, a furnace was set up. Rivets were placed in the furnace and heated to glowing hot (often to white hot) so that they were more malleable and easily deformed. The rivet warmer or "cook" used tongs to remove individual rivets and throw them to a catcher stationed near the joints to be riveted. The "catcher" (usually) caught the rivet in a leather or wooden bucket with an ash-lined bottom. The catcher inserted the rivet into the hole to be riveted, then quickly turned to catch the next rivet. The "holder up" or "holder on" would hold a heavy "rivet set" or dolly or another (larger) pneumatic jack against the round head of the rivet, while the riveter (sometimes two riveters) applied a hammer or pneumatic rivet hammer to the unformed head, making it mushroom tightly against the joint in its final domed shape. Alternatively the buck is hammered more or less flush with the structure in a counter sunk hole. Before the use of pneumatic hammers, e.g. in the construction of RMS "Titanic", the man who hammered the rivet was known as the "basher". Upon cooling, the rivet contracted and exerted further force, tightening the joint.