Michael Lange Music Company

"Connecticut's Finest Resource for the Aspiring & Professional Musician"

"Flute Padding with the Magnehelic"

 

Joseph Butkevicius

Clinic Overview:

This clinic will demonstrate incorporating the magnehelic for flute repads.  Technical information will include controlling key angles, pad exposure, and pad compression. Leveling tone holes, adjusting venting heights, final seating and regulation procedures will be given. 

Disassembly Procedure:

1.    Check for damage

The first step is to inspect for bent bodies and any noticeable damage before disassembly.  These should be corrected as part of the disassembly process.  These type repairs include body damage, severe tone hole damage, broken or missing parts, etc.

NOTE:  DO NOT try and straighten a steel with pin holes in the usual way.  You will break the steel at a pin hole and need to replace the steel.  Don’t do it!

2.    Level Tone Holes

Leveling the tone holes and dressing the edges is the next step.  If you file, the edges will need to have the burrs taken off so that the pads will not prematurely tear.  Straubinger tools work nicely for this, but other methods utilizing scrapers, cratex bits and other methods can be used.  Check flatness of tone holes with a gauge.  A simple one can be made using Larry Naylor’s tone hole facers method.  Use a leak light to sight for unevenness.  The flatter the tone hole, the easier it will be seat it. 

NOTE:  You can only file a tone hole so much.  Better to be safe than sorry!

3.    Disassemble and clean

If buffing/polishing will be done, you will need to unpin the mechanism to prep for buffing.  A safe place to keep pins and clutches is to reattach them to the steel where they belong.  Pins are not interchangeable! Dry the mechanism and reassemble with fresh oil.  NOTE: Once you begin the washing procedure, you cannot leave it overnight.  Dry it thoroughly and reassemble so rust does not form.  Polish the steels with your method of choice.  I prefer micro mesh 2400 grit. 

SAFETY TIP:  When buffing trill keys, do not hold them at the ends!  Support the key with your fingers near the wheel!

Assembly Procedure:

1.    Install Pad and Adjust Key Y Arm Angles

It may be necessary to adjust the key cups at the y arms to allow for proper pad exposure.  This can be accomplished using pad cup dies with adjustments being made off the flute.  (Demonstration will be included)  The important specifications to achieve are as follows:

If the pad nut height is not level with the key cup plane, you can replace the pad nut or simply install a different thickness pad.  (Then adjust the key cup angle.) The washer or grommet compression on the pad face should not exceed the .016” spec.  Exceeding this will compress the pad too much making it firmer, dish the face you will be trying to seat, and introduce harsh wrinkles on the skin.  If you crush a pad in the cup, it will not be able to perform as well as it can.  That will make padding more difficult.  Achieving a uniform pad exposure is highly desirable.

2.     To install the pad

TIPS:

You do not need to place hot metal onto a pad face to eliminate the wrinkles.  Simply wet the pad and blot with a paper towel.  There is no need to distress the pad face and risk burning the skin. 

Adjusting the Y arm angle can be done one of two ways.  You can do this before installing a pad with a feeler gauge of the appropriate thickness placed between the key cup and tone hole.  This is called “gapping the cup”. If you do this first, you can add foundation washers until the pad seats on the tone hole.  The second way is install the pad by feel with the correct exposure by examining the washer or grommet compression.  Then adjust the angle until the pad seats. 

If you need to remove a pad for adjusting, index both the pad and washer/grommet.

 

Using the Magnehelic:

1.    Setting Up The Magnehelic

Turn on the machine.  Adjust the flow meter, (small knob) until the ball is at the 1.0 level.  Next, adjust the large knob until the needle settles at 8. 

2.    Checking pads

Plug unused holes with rubber stoppers.  Assemble and seat pads in this order:  

3.     Checking seat against the meter

Use as light a finger pressure as possible.  The meter reading should be as low as possible.  Anything under 2 for normal finger pressure is indicative of a good pad seat.  Use a feeler gauge if you have not achieved this meter reading to find where the leak on the pad face is.  The magnehelic will indicate only if the pad is correct or not.  It will not tell you specifically where on the pad face a leak is occurring.  A feeler gauge of choice is still used for this purpose.

     TIP:  Do not pull a feeler gauge across the pad face.  Close the key cup down lightly and feel for a tug.  Pulling cigarette paper type feeler gauges will ruin the pad skin. 

     If the flute has open holes, wet you fingers before using the magnehelic or use plugs.  The magnehelic will detect dry skin and subsequent leaks where the finger tips won’t seal on the open hole. 

4.    Final check

With each pad individually tested or a section at a time, check the whole flute against the meter before clamping.  The meter reading should be at least about a 4.  If you squeeze a little tighter the meter should fall below 2.  Too check each pad individually, squeeze slightly except for each key at a time with slight finger pressure.  With each individual check, the meter should fall rapidly if the seat is correct on any individual pad.  If the flute passes this test, it will play fine as it is (when regulated).  Any heating and clamping at this point is a little added insurance. 

5.    Regulation

The next step is to regulate the adjustments.  I use a feeler gauge and double check with the magnehelic. 

6.    Set the key heights. (Make sure you have regulated first!)

Venting height are .110” for the trills and vent, .125” for the main body and .135” for the foot joint.  Use material of choice (felt, cork, scotfoam, etc.)  Remove thumb key first, then:  

7.    Heat and Clamp

The flute, at this point, should play just fine.  This step is just to put a slight impression in the pad.  I use a leak light as a heat source.  When the flute is hot, leave clamped until cool.  Remove clamps.  The whole process takes only about 15 minutes.

If you have any questions and/or comments, send an  e--mail.

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