Thursday, February 27, 2014

Ductility


Signature flutes (all have drawn tone holes).
Recently, a customer inquired as to why he could not buy a Custom Aurumite 14k, 14k white gold, or platinum flute with drawn tone holes.  We had the chance to speak with Powell’s President, Steven Wasser, to find the answer…

Closer view of the Signature flutes.
Mr. Wasser explained that the reason why drawn tone holes were not an option for flutes made from these metals is because of the metals’ ductility.  Ductility is essentially the metal’s capacity to be drawn out into a different shape (without breaking).  If a metal has a high level of ductility, it would have the capacity to withstand the tone hole drawing process.  In this process, Wasser explains “the tubing is pulled out of a small hole in the flute body into a tall ‘chimney’ to form the tone hole.   It is then rolled over and flattened to create the surface for the pad to close against” (from the post Tone Holes - Drawn or Soldered?, May 16, 2012). 

Super close-up on drawn tone holes.
All metals have a ductility level, and both white gold and platinum have reduced ductility – therefore, they do not flow the same way a much more ductile metal like silver would.  Aurumite is comprised of two different metals – one outer layer of silver, and one inner layer of 14k gold.  Silver and gold have differing levels of ductility, and the layers will want to move at different rates (with silver wanting to move faster than gold).   Although a numeric value is not always given for a metal’s ductility, a certain level is needed for the metal to be successfully drawn into tone holes.  Wasser states that a “100% success level is needed,” so if even one tone hole does not form properly in the drawing process, drawn tone holes would not be an option for that particular metal.  In this case, it would be the Aurumite 14k, 14k white gold, and platinum.

Friday, February 21, 2014

Silver Headjoint

.016" silver headjoints (Aurumite 14K on far right)
We recently had an inquiry from a customer about silver flutes with .018" tubing thickness.  He asked why there is not an option of a silver .018" thickness headjoint to go with the flute.  He said, "Wouldn't it fit in a .018" body?"

The answer to the question involves barrel thickness and headjoint thickness.  For a .018" silver flute, the barrel is .016" thick.  Therefore, the headjoint is .016" to fit the barrel.  Also, Powell designs and tests headjoints to have the best possible sound qualities, resonance, and response.  Different thicknesses are tested, and when the .018" thick headjoint was tested, it was found to be too heavy -- it did not have the response and resonant properties that were optimal for a headjoint.  It is possible that some people could get a .018" thick headjoint to respond favorably, but for the majority of flute players, it is simply too dense and heavy.  So, there you have it!  The .018" thick silver Custom flutes have a .016" thick silver headjoint to fit the barrel and to produce the best possible sound.

Sunday, February 16, 2014

Cutting Headjoints

To select "the" perfect headjoint, flute players must evaluate the headjoint on many levels.  After catching up with flute finisher, Lindsey McChord, in the headjoint cutting room, we discovered that the careful assessment of a headjoint's qualities starts long before it reaches the player's hands.  In fact, it begins in the headjoint cutting process...

Lindsey was cutting a Soloist headjoint when we stopped in to see her.  She gave us an overview of the process, which involved several steps of visual inspection inside and out, careful measurement of size and angles, marking, scraping, sanding, and polishing.  Since Lindsey must assess areas inside the headjoint, she uses a small mirror to help her see those areas as well.  She uses a few electric tools for sanding and scraping, but the majority of her work is simply cutting the headjoint by hand with a hand scraper.  Even in the steps of the process where she uses bench motor attachments, a tremendous amount of skill is needed to maneuver the headjoint with these tools properly.  As you can imagine, she is working with very small areas when she is cutting, sanding, and polishing.  The process takes extreme control and the ability to feel what you are doing.

After Lindsey is finished cutting a headjoint, it is then evaluated.  The actual cutting and subsequent evaluation are the two most time consuming parts of the process.  The headjoint must be play tested and compared to the model for its style (there are currently four Powell headjoint styles).  If the headjoint is not exactly the way she wants it, she must take it back and re-evaluate.  Her task at this point is to examine and assess what exactly is making the headjoint different -- and the differences can be very small.  She told us, "you have to look at the headjoint and be hypersensitive to microscopic things.  You have to be very intense and not be distracted by other things."  In this part of the process, she shared that the mirror is very helpful, because certain things can only be seen this way.

Theoretically, all headjoints of the same style are cut to be exactly the same -- yet they may not be.  There may be tiny differences that will make them play differently, and Lindsey uses the skill she has developed in cutting headjoints along with her skills as a flutist to detect these differences and make any further adjustments.

Measuring angles.
Measuring width.
Sanding.
Cutting with the hand scraper.
Riser after being cut and polished. 
A few tools used in the process.  The mirror is critical for seeing inside.


Friday, February 7, 2014

Fitting a Footjoint - Part II

We were upstairs on the production floor earlier this week when we ran into flute finisher Lindsey McChord fitting a footjoint.  We had a previous post on footjoint fitting (you can see the post by clicking here), but that post detailed how to fit a footjoint when the body tenon was too big.  So, what happens when the tenon is too small?  We had the chance to find out!

When we caught up with Lindsey, she had a Conservatory with a body tenon that was just slightly too small for the footjoint.  Additionally, Lindsey felt a bit of "rocking" when she placed the footjoint on the tenon, so she needed to expand the body tenon just slightly.  To do this, she placed the body on an arbor and began burnishing the tenon.  Burnishing is a process where the metal of the tenon is pressed against the metal arbor.  By doing this, the tenon metal expands from the pressure.  However, the pressure has to be very light, and you have to exert equal pressure all around.  Because the process is so delicate, Lindsey began by burnishing the tenon in about three spots.  She then tested the fit, and it was still a bit loose.  The initial three burnished spots on the tenon were visible as lines that had a bit of a "matte" finish.  Since she could see the initial marks, she then burnished the tenon in a few more spots between the areas that were burnished in the previous step.   Once again, she tested the fit.  It was good -- even a bit on the tight side.

Now that the fit was almost perfect, there was one more step needed to remove any marks from the burnishing process and get a perfect fit.  To do this, Lindsey used very fine-grade sandpaper on the tenon.  The rough side of the sandpaper is good for removing slight bits of material, so Lindsey sanded a bit with that side of the paper.  However, she also used the opposite, smooth side of the sandpaper to smooth out any marks.  Then, she took a tissue and wiped both the outside of the body tenon and the inside of the footjoint.  This helped remove any debris that might hinder a smooth fit.  After this, she tested the fit of the tenon once again, and it was perfect.  She then added the final step of a bit of polish to shine and smooth the tenon, and it was ready!

Recapping the process, it may seem simple enough, but it truly takes great skill and patience.  Every step in burnishing must be done in very small, light increments -- but the most important skill is the ability to feel the fit.  It's much more than a matter of  "too tight" or "too loose."  One must be able to assess the fit on many levels and feel the slightest imperfections.

Checking the fit of the footjoint.  It is a bit loose and "rocking."
Placing the body tenon on an arbor.
Burnishing the tenon with a burnishing tool.
Burnishing marks -- these serve as a guide, too, for additional burnishing.
Checking the fit again.  Just a tiny bot too tight now.
Sanding the tenon to remove marks and make it just a bit smaller after burnishing.
Using the opposite side of the sandpaper to smooth out the tenon.
Cleaning out any residue in the footjoint.  This was done on the tenon as well.
Checking the fit again -- perfect now.
After polishing, the tenon is shiny and smooth.  Done!