Friday, January 4, 2013

Fitting a Foot Joint

We recently caught up with flute finisher Lindsey McChord as she was about to fit a footjoint.  It seemed to be a great topic in our opinion -- especially since we discussed headjoint fitting in a previous post on our repair blog at

Footjoint fit is too tight and needs to be adjusted.
Lindsey told us that headjoint and footjoint fitting are basically the last steps in the finishing process.  Specifically, Lindsey prefers to fit the footjoint first.  When we caught up with her, the footjoint she was fitting was too tight because the footjoint tenon on the body was particularly heavy at the bottom (toward the edge).  In order to correct this, Lindsey placed the flute body on a piece of equipment known as an "arbor," which holds it in place and keeps it from moving.  She then sanded the tenon to achieve the correct fit.  Very fine sandpaper is used in this process (usually 800 or 1200 grit).  However, the process of sanding does not actually take material away -- it simply smooths the material out and makes for an even fit all around.  When sanding the tenon, it is important to make little changes bit by bit, always checking the fit in between.  Lindsey assembled the footjoint on the body to check for any rocking motion (both vertically and horizontally) after each slight sanding.  It's important to check both of these directions for rocking motion, because if the footjoint tenon is not completely round, you may feel rocking in one direction but not the other.  Any heavy areas are sanded first (in this case, the bottom of the tenon), and then the tenon is sanded all around.  Once again, she checks the fit after each slight bit of sanding.  The sanding/checking process is repeated until the perfect fit is achieved.  Luckily, it only took a few steps to adjust the tenon so that it was smooth and fitting perfectly with the footjoint!

Tenon is a bit "heavy" at the bottom as you can see from the line on the tenon.
"Arbor" used to hold the flute in place.
Body placed on the arbor to sand the tenon.
Sanding the tenon with a small piece of sandpaper, focusing on the heavy area.
Checking the footjoint fit.  This step is repeated after every adjustment.
Sanding the entire tenon with a larger piece of sandpaper to smooth everything out.
Tenon is smoothed, even, and perfectly fit with the footjoint!

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