Friday, November 22, 2013


If you've ever heard the term "swedging" from your repair technician and wondered what that meant, we are here to answer that question!  We stopped in to see Repair Technician, Rachel Baker, and ask her about the process.

With normal wear and tear, mechanism tubing loosens.  Extra motion in the mechanism caused by this loosening is what is known as "play."  You can read more about "play" in a previous post here at  When there is too much play, the mechanism can actually move from side to side.  To tighten the mechanism back up to where it should be, your repair technician will "swedge" the mechanism tubing.

Swedging requires a special "swedging tool."  Rachel uses a "vise" to hold the swedging tool as you will see in the photos below.  She begins by running a steel through the mechanism tubing and then places the tube (with the steel inside) in the swedging tool.  She says that it is important for the steel to have a snug fit through the tubing.  If a steel is too loose, the metal tubing will get crushed during the process.  The tip of the swedging tool is comprised of three parts that can contract when tightened and expand when loosened.  When you are swedging, the tip contracts down onto the tubing.  Rachel turns a handle on the back of the swedging tool to tighten the tip down onto the mechanism tubing.  She does not want it to be too tight, because she needs to be able to turn the keys on the mechanism tubing.  The pressure exerted onto the mechanism tubing from the swedging tool lengthens it (or "draws it out"), because, as Rachel says, "The metal has no place to go but out."  She then turns the key around the tubing to "burnish" it against the inner steel.  After this, the swedging tool is loosened to release the mechanism tubing and steel.  Rachel then puts the tubing back into place on the flute and checks the feel.  She says that the best way to swedge is to do "a little bit at a time," so the process takes a few cycles of swedging and then checking the fit.

One point that Rachel made is that mechanisms will always have a bit of play -- and that is normal.  However, if there is too much play, the tubing will move too much and will need to be swedged.

Rachel places the tubing and steel in the tip of the swedging tool (which is held by the blue vise).
Tightening the tip of the tool onto the tubing and steel.
Close up of the tubing and steel in the tip of the swedging tool.  The tubing is fairly short -- the steel running through it is much longer.
Even closer here -- you can see that the tip of the swedging tool is in parts (sections).
Rachel turning the key around the tubing to burnish it against the steel.

Placing the key section that was swedged back on to the mechanism.
Checking for movement in the section to tell if more swedging needs to be done.

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