Wednesday, July 25, 2012

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: 

 
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

Wednesday, July 18, 2012

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

video

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”!

Wednesday, July 11, 2012

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.