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 http://www.repairmyflute.com/2012/09/headjoint-fit.html. 

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!

                                                            

Hand Shaped Corks

You've probably heard the term "hand shaped corks," but what does that mean?  Are these corks on your flute really shaped by hand?  Well, the answer is yes!  We recently caught up with flute finisher Karl Kornfeld to take a look at the process.

Corks are used on the trill keys, G# key, and D# key.  Powell receives a supply of corks in the shape of small "barrel-type" pieces -- similar to a cork from a wine bottle.  One cork piece will be used for the 4 keys mentioned above.  The cork is first cut into quarters.  Karl prefers to take one of the quarters and then cut that quarter in half for the trill keys.  This helps with consistency and allows for these corks to (aesthetically) "match."  When we caught up with Karl, he was working on a D# cork.  For this key, he uses one of the cork "quarters."  He uses contact cement on one side of the cork and the back of the key.  Then, he presses the two together and holds them (with the help of some equipment) until the glue is dry (about 10 seconds).

Now the shaping process begins.  The cork must be shaped so that the key opens to a standard measurement that Powell uses on their flutes.  A cup height gauge is used to periodically check the height of the key cup opening as the cork is shaped.  Finishers use a combination of double-sided razor blades and various grits of sandpaper (220, 400, 800).  The higher the grit, the finer the sandpaper.  Karl puts the key mechanism back on the flute and marks the cork in the center, where the cork touches the center of the "box" (box is the area between the sides of the ring).  He then begins to shape the cork with the combination of sandpaper and razor blades.  In the photos below, the thin strip of sandpaper is 220 grit, and the larger piece is 400.  The 800 grit is used for very fine adjustments.  He continues sanding and shaping the cork until it is the correct size and shape for the key to open properly at the calculated height -- which is critical. 

There are other mechanisms which have cork for adjustments, and for these, small slices of the original cork are used.  So, now if you hear the term "hand shaped corks" with Powell flutes, you'll know that they are truly hand shaped by our finishers!

It begins with a piece of cork.

Cork piece divided into quarters.

One quarter piece for the D# key.

Applying contact cement to cork (and then key).

Pressing key and cork together.

Holding key and cork together until glue dries.  Leather strip is used to protect key.

Shaping cork with razor.

Marking center of cork where it meets center of the "box."

Sides of cork should not touch sides of ring.

Some shaping with a 220 grit strip of sandpaper.

Checking key opening with cup height gauge.

More shaping with a 400 grit piece of sandpaper.

Finished!

Quarter cut in half to match trill key corks.

Slice of this piece used for adjustment cork.

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!

"Pin Pals" - Part III

Pinless: Should We Care?

If Powell and other flute makers are using pinless designs there must be a good reason.  There are, but first let’s review what’s good about the traditional pinned mechanism.

·         It’s easier to make the flute with pins, so the cost to buy the flute is lower.

·         Repairs of pinned flutes are generally easier.  This is especially true if the repair person is not well versed in pinless mechanical designs.

·         Pinned flutes are lighter than pinless flutes.

The pinless mechanism is more complex to build and repair, but it produces a smoother, more reliable mechanism.  Here’s why:

·         A pin is a very small piece of metal, like a short, skinny sewing needle.  As a result the pin can torque or twist when the keys are pressed down or rotated.  The torquing motion can cause keys to bind or go out of adjustment.  The bridge used in pinless mechanisms is heavier and stronger than pins.

·         The more rigid bridged construction associated with a pinless mechanism tends to produce a very smooth, clean action.

Excellent flutes are made with both pinned and pinless mechanisms. 

"Pin Pals" - Part II

The Pinless Mechanism

The Brögger Mechanism, developed by Johannes Brögger in Denmark, popularized the pinless mechanism.  Yet we know that pinless foot joint keys existed for decades before the pinless mechanism with a trademarked name.  

Perhaps the Brögger mechanism was the first pinless center joint mechanism?  No – to the best of our knowledge Pearl was using a pinless design on some its center joint keys before Brögger. 

And for the last 25 years Powell has had its own unique, neat, underslung bridge in the left hand.  So was the Brögger mechanism truly groundbreaking?  The Brögger Mechanism is a pinless system that includes both the right and left hand of the flute.  This design uses bridges and adds what look like two extra back connections to the flute.  

Underslung?

Keys can be bridged over the top of the regular key tubing where the extra mechanism is very apparent, or underneath where it is unobtrusive.  Powell’s pinless mechanism uses underslung bridges to maintain the aesthetics of the traditional flute design while providing the benefits of contemporary flute construction.

In 2009 Powell added a neat, sleek underslung bridge in the right hand to complement the underslung bridge its flutemakers had been using in the left hand for 25 years.  All of today’s Powell Custom and Conservatory flutes come standard with Powell’s pinless design.   Signature flutes continue to be made using the tried and true pinned mechanism.

Welcome!

Welcome to Flute Builder!  We're glad you stopped by.  This blog will feature articles and photos on the craft of making handmade flutes.  If you are curious about the process, you have come to the right place!  We will discuss methods, materials, options, design, and many more topics.  We'll answer your questions and encourage you to join in the discussion.  Thanks for coming over to the Flute Builder blog.