A Steamy Topic: Taming Tenon Corks

By Windworks Studio of Philadelphia

Bev and Linz (“The Girls in Philly”)

Musical instrument makers and repair technicians don’t need to be reminded that quality cork is hard to come by. In fact, it is pricier than fine perfume. Good cork has to be hand-picked and there are industries who, like ourselves, find few or no workable substitutes. Cork is alive, it breathes, it wicks moisture and is forgiving on tenons and tone holes. Cork can also tear, burn and crack when we place it - particularly if it is not premium cork. In fact, the quality designations seem to have shifted as cork commodity has become harder to access with rising demand. What used to be considered a “moderate” grade is now often labeled as “premium”. 

Torn piccolo tenon cork in need of replacement.

What do you do when you are replacing a piccolo tenon cork and the cork you have is less than ideal?

Ideal premium sheet cork on left, and less than ideal cork on right.

We all know that cork to be placed on a piccolo tenon has a tendency to crack, especially with less than ideal cork.

Well, here is a simple tip that just might make your day easier!  Cut your cork, sand and adjust the fit. To ease the strain on your cork and improve workability, place your prepared cork over a whiskey glass filled with steaming water. 

Cork strip placed over a whiskey glass filled with steaming water. Notice the curling.

As the cork steams, it rehydrates, curving just enough to make a flawless placement much easier. Be sure to apply your adhesive of choice after the cork has been steamed. You are now ready for some Stars and Stripes!   

 Adapting cork to piccolo tenon with ease of workability.

"Play" In Mechanism

Have you ever heard the term "play" when speaking with your repair technician?  They may have mentioned that the mechanism had a little "play" in it -- which actually is not always a bad thing.  But, what exactly does this mean?  Flute finisher Karl Kornfeld discussed this term with us as it applies to flute repair.  He explained that play usually refers to lateral movement of keys within a section or of an entire section (of the mechanism).  Depending on which key or section, a small amount of play may be necessary for proper function.  Play can be caused by normal wear and tear, loose or poorly-fit screws, or damaged posts.  Different flute types (for example - pinned or pinless) have different rules regarding how much and where play is acceptable.  Excessive play -- especially to the point of rattling -- is definitely not good.  If you think there might be excessive play in your flute's mechanism, make sure to take it to your technician for proper evaluation.

Arrows indicate the lateral motion of "play"

Another area on the mechanism where "play" may occur

Lost Motion

You may have heard the term "lost motion" from your repair technician and wondered what exactly that meant.  We met up with flute finisher Karl Kornfeld here at the Powell shop to help shed some light on this term.  Karl explained that lost motion is a delay between pressing a control key and movement of the slave key.  For example, when depressing the left hand second finger, both keys should move together in unison.  If there is a delay before the slave key is "caught," then you have lost motion.  Lost motion can be caused by faulty adjustments or incorrect key-height settings.  As always, if you notice lost motion in your mechanism, the best solution is to take your flute to an authorized repair person.

Karl is depressing the control key, and the "slave" key is directly to the right (looking at the picture from the front).

Both keys should move together in unison.

If the slave key is delayed in closing, there is lost motion.

Binding Issues

If you've ever taken your flute in for adjustment because of the mechanism not feeling resistant or just not "quite right," you may have been told that the keys were "binding."  What exactly does that mean?  Well, in simple terms, it means that something is preventing the keys from moving freely.  Binding happens when things are interfering with each other that should normally not be in contact.  Often times, two pieces of metal are rubbing against each other, which would cause the key mechanism to bind.  This could happen if the posts are misaligned or if the steel inside the mech tube is somehow bent.  Posts and other parts of the mechanisms where pieces of metal come together are areas that are susceptible to problems that could cause key binding.  The photos below identify a few of these areas on the footjoint.

Another culprit of binding keys is simply dirt, grime, or corrosion.  Key mechanisms need to be cleaned out properly, so make sure to take your flute to a qualified repair technician for regular maintenance.  You and your flute will be happy you did!  

Inside the Tube

We recently caught up with our repair technician when she was in the midst of disassembling a flute for a COA.  We spotted a pinned mechanism at her workbench, which prompted us to think a bit more about pinned and pinless mechanisms.  All Powell Signature flutes are pinned, but Conservatory and Custom flutes are pinless.

Seeing the pinned key mechanism sparked our curiosity.  Our technician explained that the pin holds the key in place on the outside "mech tube."  But, just where exactly is the pin going?  Having read about the different feel and operation of pinless and pinned mechanisms, we wondered what other differences there might be in these mechanisms that are not exactly visible from the outside.

Our technician explained that with a pinned mechanism, the outer mech tube has an inner steel running through it.  To hold the key in place, the pin goes all the way through the key, outer mech tube, and inner steel.  The mech tube, complete with pinned keys and the inner steel, is then held into place between the posts with pivot screws.  With a pinless mechanism, there is also a long steel inside the mech tube, but this steel (itself) actually screws into the posts.  There are no pins (obviously) running through the mech tube and its inner steel.  The keys operate with a bridge mechanism.  The pinless bridge mechanism also has small pieces of cork on the back -- which your repair tech works with to make adjustments. 

We had an excellent three-part series on the pinless mechanism written by Powell's president, Steven Wasser, for our Flute Builder blog.  There is also a terrific two-part video of Mr. Wasser explaining the differences between pinned and pinless mechanisms on our YouTube channel.  Make sure to take a look at the posts, and definitely check out the video!

Links to Blog Posts from Flute Builder: Pin Pals
http://www.flutebuilder.com/2012/04/pin-pals-part-i.html,
http://www.flutebuilder.com/2012/04/pin-pals-part-2.html
http://www.flutebuilder.com/2012/04/800x600-normal-0-false-false-false-en.html

Links to Videos on Pinless Mechanism: 

http://www.youtube.com/watch?v=gr1UUDoL_Z4 

http://www.youtube.com/watch?v=ijDBAk7K3w0&feature=channel&list=UL

 

Pin Holds Key in Place on Pinned Mechanism

Underside of Pinned Key

Pivot Screw in Post to Hold Mech Tube with Inner Steel

Inner Steel from Pinless Mech Screws Into Post and Runs Through Mech Tube

Pinned Mechanism on Assembled Flute

Bridge from Pinless Mechanism on Assembled Flute

Sneaky Leaks

Windworks Studio of Philadelphia

Bev and Linz (“The Girls in Philly”)

Any leak, no matter how small, affects the sound and speed of flutes - not to mention the extra work required to have the flute perform.  What’s important to remember is that leaks are not limited to pads, their installation or to tenon fit.  Insidious leaks can hide in the headjoint!  These types of leaks are tricky to locate and are only solved by accurate diagnosis.

Obviously, head cork leaks are more common than leaks from other parts of the headjoint. So, here are some tips, as well as a foolproof step-by-step approach to find the problem.

Always and often:

Step 1) Pressure test the headjoint on the Magnehelic with the head cork in place.  You want a perfect zero.  If it zeros out, the headjoint is “OK.”

Fig 1: Correct Pressure Test reading at “Zero.”

If it fails to zero out, before you replace the cork, do the next test in Step 2;

Fig. 2: Initial Pressure Test Failure with head cork in place

Step 2) Remove the head cork assembly.  Put in a rubber stopper.  Pressure test the lip plate assembly and tube joints.  Does it zero out?  If not, try the next test;

Fig 3: Pressure test with rubber stopper  (head cork assembly removed)

Step 3) Submerge the headjoint in water while pressure testing.  Bubbles will lead you to the leak location.  What to do now?

Fig 4: Movie of Solder Failure Lip Plate assembly water test under pressure

Step 4) Unless, you are a headjoint maker, it’s best to send the head joint back to the maker for the leak to be addressed.  It may be helpful to review an earlier post written by Steven Wasser on different types of solder techniques, titled “Why Solder Matters” a June 6, 2012 entry on the Flute Builder Blog. 

Enjoy your work and remember when you want to be a “perfect zero”!

Very Fine Adjustments

You've probably sent your flute in for an overhaul or COA and heard your repair tech talk about "adjustments."  Adjustments are made to key mechanisms so that the keys work together properly.  If the keys are not working together properly, you will definitely notice -- because you will not get the correct notes out!

Powell flutes have different adjustment features depending on the model.  Powell Signature flutes have adjustment screws.  However, Powell Handmade Conservatory and Handmade Custom flutes do not have adjustment screws.  In fact, it may be difficult to see, but the Handmade Conservatory and Handmade Custom flutes have paper that is affixed to the metal with shellac.  Your Powell technician uses extremely fine-grade sandpaper (1200) to make changes to the thickness of the paper when s/he is adjusting the mechanism.  Adjustment screws are definitely more common that paper, because it takes less time to work with adjustment screws than it does to work with paper.  However, paper is much more stable and allows the technician to really "fine tune" the mechanism.  If your flute has adjustment screws or adjustment papers, never fear -- your technician knows what to do to make sure your flute is in tip-top shape!

Handmade Conservatory and Custom Flutes use adjustment papers.  You'll see a very small black paper just above the open hole key pad in this photo.

Signature Flutes use adjustment screws as you can see from the mechanism on the left.

Comparison of the different mechanisms.  (Top of photo): mechanism with adjust paper.  (Bottom of photo): mechanism with adjust screw.