Wooden Flute Tone Holes -- and More

If you've looked closely at the tone holes on a wooden flute, you may have noticed that they look a bit different from tone holes on metal flutes.  At Powell, metal flutes have either drawn or soldered tone holes, but those choices are not possible with a wooden flute body.  After all, with wood, you wouldn't have the option to solder something onto the body or "pull" the hole up from the body.  No, wood is definitely not as flexible as metal.  So, how exactly are the tone holes formed on the wooden flute?  Are there other differences in how the holes are covered by the keys?

The answer is rather simple, actually.  It's all about subtracting material and sculpting the wood.  With a wooden flute, the tone hole is cut out of the body in a process that is referred to as "milling." However, after the tone hole is milled, more material around the hole must be removed to allow clearance for the key cup.  Since it is a wooden body, you are actually carving or sculpting the wood to create the convex shape around the tone hole.  The tone hole itself has a flat edge, so the key mechanism functions exactly the same as it does on a metal flute.  The key cups and pads are exactly the same size and shape as those on a metal flute -- and they cover the hole exactly the same way as they would with a metal flute. 

But what about the rest of the body?  Is it the same thickness as metal?  Obviously, no.  A wooden flute body is thicker than a metal flute body.  The wood has to be thicker so it doesn't crack.  However, the inner bore diameter of a wooden flute is exactly the same as the inner bore of a wooden flute.  So, there are some differences with the wooden flute but many more similarities. 

Wooden flute bodies before and after tone holes are cut.

Close-up on the tone holes (notice carved covex shape around hole for key clearance)

Final assembly with keys in place.

The New Powell Sonaré Piccolo

You've probably heard some buzz going on about a new piccolo from Powell.  Just what exactly is different about this, and when will it be available?  Well, there are several unique features, and we will be debuting this piccolo next month at the 2012 NFA Convention in Las Vegas, Nevada.  If you are attending, make sure to stop by the Powell booth (#317) and see us! 

The new Powell Sonaré piccolo was designed with elegance and durability in mind.  The body is made from an American hardwood that is available in three different color choices: American Amethyst, Indian Onyx, Tuscan Umber.  The photos below show the piccolo in "Indian Onyx" and were taken during a builder's workshop sponsored by NABIRT last April in Pennsylvania.  The keys are square as you can see, and they are made of stainless steel.  This feature is especially nice since stainless steel will not tarnish.  Although the keys are square, you'll also see from the photos that the tone holes and pads are still (traditionally) round.  The stainless steel keys are also available in "golden steel."  Golden Steel is comprised of a high tech ceramic coating over stainless steel.  The finish is durable and a golden yellow color which provides the appearance of yellow gold without the cost.  Additional specs on the piccolo include: 

• A-442 pitch

• Modern Powell scale

• Pisoni Star Pads

• Stainless steel springs

• Classic style hand cut headjoint

You might be wondering, "Well, where exactly is this piccolo made?"  The answer is right here at the Powell shop in Maynard, MA!  Handmade just like all the Powell flutes and piccolos.  Hope you will have a chance to try it!  For more information, we have a terrific video on our website -- take a look at http://www.powellflutes.com/blog/brand-new-powell-sonar%C3%A9-piccolo.  A full article from MMR Magazine may be found at http://www.mmrmagazine.com/5748/current-issue/forging-new-paths-powell-flutes/.

Polishing to a Perfect Shine

So, how exactly do our flute headjoints get so shiny?  Well, they certainly do not start out with a perfect shine.  We recently caught up with our shop manager and one of our polishing technicians.  As you can see from the photo below, when a headjoint arrives at the polishing room, it is far from "shiny."  It actually goes through several steps before the final result.  In pre-prep polishing, grease is applied to the headjoint, and the headjoint is then buffed on a specially-tuned buffing machine.  The buffing machine has a wheel made of cloth used to buff and polish.  Pre-prep polishing is an important step since it allows the technician to clean up any solder and imperfections.  This step also polishes the headjoint to some degree to make it shiny.  After each buffing and polishing step, the headjoints are cleaned in an ultrasonic cleaner.

The final step in the polishing process is where something known as "rouge" comes in to play.  It may sound like an item from the cosmetic department, but it is a polishing compound that is made of iron oxide (rust) in a wax base.  It gets its name from its color as you can see!  The rouge is applied to the buffing wheel, and the headjoint is polished.  Rouge is excellent for polishing because it has very fine particles that remove metal in smaller pieces, thereby producing a very high shine.  In addition to our flute builders using rouge as a polishing agent, jewelers use it as well.  Makes sense to us since our flutes are made of precious metals!

Headjoints in an early phase of polishing

Rouge for the final step

Technician applies rouge to the cloth buffing wheel in the final step of polishing

Headjoints that have been polished and are ready to go!

After Market Customizations

Is it possible to customize your flute with some optional features after you've purchased it?  The answer would be a solid "maybe," depending on the flute.  Each flute must be analyzed on a case-by-case basis.  Here at Powell, there are some options that can be added after the flute has been purchased.  Regardless of whether you have an in-line or offset G, there are certain options that are available.  For a C# trill or split E, the flute would have to be analyzed by the repair tech to see if it would be possible to add these.

Enclosed D# Roller

There are a couple of options that are definitely possible, such as a G disc, which can always be added.  If you are interested in adding a B foot or C foot, that is available as well.  You can order a B or C foot, and it will be made in the shop.  You could even choose a different metal if you would prefer.  You would need to send your entire flute to the shop to have the new B or C foot fitted to the instrument.  Also, a D# roller could be added, although it would have to be an "enclosed" roller (as seen in the photo on the right).

Customizations can always be considered for Powell Signature, Conservatory, and Handmade Custom flutes.  Unfortunately, there are certain models that we are not able to customize after purchase, including Powell Sonaré models, the Powell 2100, and the Powell 3100.  Options are not available on the Powell Sonaré flutes because the mechanism is different from a Powell custom, and the keys are plated.  The 2100 and 3100 also have mechanisms and key shapes of a much different design than a traditional Powell model.  Powell aftermarket options are only available on Powell flutes and not on other brands, unfortunately.  If you are considering an after market customization, make sure to contact our repair technician to see what might be possible.  Our technician, Rachel Baker, can be reached at rbaker@powellflutes.com.

Are Old Flutes Better?

By Steven Wasser - President, Verne Q. Powell Flutes, Inc.

Flutes have come a long way in the last 100 years, yet many musicians prize old Louis Lot, Haynes, and Powell flutes.  Flute scales are better today, precision machining produces superior parts, synthetic pads are more stable, and silver is silver – or is it?  Does something happen to silver over time that could have a beneficial effect on sound?  In fact silver does change over time.  It stress relieves and age hardens. 

Steven Wasser giving tour of Powell production facility

When any metal is worked, such as by cutting, extruding, or bending, it becomes stressed.  In its “relaxed” or unstressed state, the molecular structure of metal looks something like graph paper, with a nice, regular geometric structure.  When the metal is stressed, some of those boxes get scrunched up, and some become bigger and misshaped.  As a result of these irregularities the metal is unable to vibrate as freely as it would do in its pure, unstressed condition.  These irregularities can cause dead spots in a flute.  In our experience resonance is better with silver that has been stress relieved.

Hardness correlates with stiffness or rigidity.  When metal flexes it absorbs or diffuses energy.  Since flutes are very inefficient at converting your air into sound, small differences in how that air energy behaves can affect acoustical output.  We believe that the slight age hardening of older silver flutes has a positive effect on response.

Does anything else change over time with older silver flutes?  Well, yes, the instrument is subject to daily vibration from being played and is swabbed.  We cannot document what effect, if any, might arise from these activities, but some flutists are convinced that they make a difference.

Is there a way to produce some of the effects of aging on silver in new silver flutes?  Yes.  At Powell we use a variety of techniques to keep the molecules of the flute body as even as possible.  When we solder we generally heat the entire body at once, evenly, rather than spot soldering one location at a time.  And when we’re done, we cryogenically treat the entire flute.  There is solid documentation that cryogenic treatment age hardens and/or stress relieves certain metals, but data for the effect of cryogenic treatment on sterling silver are inconclusive.  Based on years of subjective testing we believe cryogenic treatment stress relieves silver and slightly age hardens it. 

Some of the qualities of older flutes may also be perceptual rather than real.  A number of years ago one of our customers was complaining that new Powell flutes did not have cups properly centered over the tone holes.  I was surprised because we use gages that are accurate to within the thickness of a human hair.  Then this customer came with Powell flute #2000 made by “Mr. Powell” which he proudly showed me.  As I looked at this flute I noticed that the trill cups were severely bent – nearly 1/8”.  Apparently when Mr. Powell made this flute the trill cups were not centered properly.  Rather than re-make the keys he simply bent them so that they covered the tone holes.  When I pointed this out to the customer he was shocked.  He somehow noticed if our new flutes cups were off center by 0.003”, but never noticed that the trill cups on Powell #2000 were grossly off center.

Beauty is in the eye of the beholder.  We have thought about the way flutes age and have tried to mate a process for aging the flute with modern elements like improved scale and keys.

Testing Flutes

One part of the manufacturing process that is extremely critical is the final testing.  Here at Powell, this is done by Rebecca Eckles, our Director of Quality and Service.  Rebecca wears many hats and is a professional flutist as well.  After the flutes are completed by the finishers, they are sent to Rebecca for testing.  She tests all the flutes and Signature piccolos.  When she receives them, they still have the protective blue film covering the body, headjoint, and keys.  Rebecca begins by checking the complete mechanism from bottom to top.  She presses each key, making sure the mechanism is smooth with no drag, no binding keys, and proper spring tension.  She also checks for lost motion and any sharp edges.  After this manual test of the mechanism, she completes a "visual check" in which she looks at key heights and padding, making sure everything is even and at the proper height.  She also inspects the corks to make sure they are well shaped and free of imperfections.

Rebecca then begins a play test.  This time, she starts from the top down to check for any leaks.  She then takes the feeler gauge to each pad as an additional measure to identify any leaking pads.  When her evaluation is complete, she submits her recommendations.  If there is anything that needs to be corrected, it goes back to the finishers.  The flute then rests for a few days, and she retests it.  Rebecca also works with the repair technician, and when everyone is in agreement that the flute is ready, it is shipped to the customer.  Regardless of the model (Signature, Conservatory, or Custom), Rebecca believes that they must all look and sound like custom flutes.  She also stresses that the finishers are master craftsmen -- their work is what makes everything work well by the time it arrives at her office.

Manually checking the mechanism

Checking for proper headjoint fit

Checking for leaks with the feeler gauge

Visual Inspection

Play testing

Why Solder Matters

By Steven Wasser - President, Verne Q. Powell Flutes, Inc.

These are photos of two sterling silver pieces which have been joined using two different techniques.  The photos were done at MIT using an electron microscope.

The top portion of the photo to the right shows a joint that has been made using high temperature silver braze at around 1400°F.  The bottom portion of the photo shows a joint that has been made using low temperature solder at around 450°F.

Does this affect sound?  Yes!  The high temperature silver braze inter-diffuses into the sterling silver, and the result is a piece of metal that acts as if it were a single piece of metal.  The low temperature solder acts more as metal glue and sits in between the two layers of metal.  In my experience vibration and resonance are superior when only a single, homogenous metal is involved.  With the low temperature joint the solder layer can act as a barrier to the transmission of vibration and can dampen response.

What about strength or durability?  With a silver brazed joint the musician should never have to worry about things like tone holes leaking or lip plates falling off flute headjoints.  The strength of a joint that has been done using low temperature solder is typically 5000 lb/sq inch.  The strength of a silver brazed joint is 40,000 lb/sq inch, 8x stronger!

Silver brazing is much more difficult to perform than low temperature soldering due to the high temperatures involved.  Also silver brazes contain more precious metal than most low temperature solders and are usually more expensive. For flutes, we silver braze our tone holes,  We also silver braze the headjoint lip plate to the wall and the wall to the headjoint tube.