Editing Swaging (section)

=== Musical instrument repair ===
In musical instrument repair the usual term on both sides of the Atlantic is swedging, not swaging, though it is generally acknowledged that the former derives from the latter. Keyed instruments such as the [[clarinet]], [[bassoon]], [[oboe]] and [[flute]] need swedging when years of key movement has worn or compressed the metal of the hinge tube they swivel on and made it slightly shorter, so that the key can travel along the rod it is mounted on instead of being held firmly between the posts attaching the rod to the body of the instrument.  This gives rise to floppy keys and a poor air-seal and needs to be corrected by lengthening (swedging) the hinge tube. This is a job that needs to be done by hand, and swedging pliers with highly polished oval holes in the jaws to fit common sizes of hinge tubes are often used to achieve this, though various proprietary designs of swedging tools are available to do the same job more efficiently.

In piano technology, swaging happens in several areas: key leads, underlever leads, and bass strings. Key leads which, in the piano's earliest history, were actually made using lead, are soft, round chunks that are inserted into holes drilled into the side of piano keys as a means of balancing actions. Key leads vary in size, generally small, medium, and large. Basically, key leads help to make a keyboard's touch light enough to play. Over time, fluctuations in humidity and aging of wood in piano key-sticks and underlevers causes space to develop around leads, causing them to rattle, tick, or knock. Loose leads in underlevers tend to be the most annoying to pianists because it's difficult to pinpoint where the noise (often a "tick" sound) is coming from. The remedy for the noise is swaging—squashing the leads with a short steel rod. Swaging the lead fills the void and eliminates the noise.

Bass strings in pianos are generally constructed with round—sometimes hexagonal—drawn-steel cores, over which copper is wound. Especially on round core wire, the last several inches of the area where the winding terminates is often flattened—swaged—to create a grabbing point for the copper winding material.