Basic Flute Pads
What Does a Flute Pad Do?
A flute pad has a simple purpose. It closes a hole in the side of the flute’s body tube, much like your fingers cover the holes on penny whistles, fifes and recorder-type instruments.
Your fingers have plenty of leaks, though. They are called fingerprints. Even if every hole is covered perfectly, there is still a large opening at the end of the instrument. It makes you wonder how many kilopascals of pressure could possibly build up inside that open-bore tube.
Because the flute is often considered one of the most difficult woodwind instruments to repair, we will begin there. After all, when it comes to woodwinds, “If you can fix a flute, you can fix anything.”
The main thing to understand is that there is nothing inherently difficult about:
- Installing pads in a flute
- Leveling flute pads
- Seating flute pads
- Adjusting a flute, provided that you pay attention
Conventional Ferree’s Flute Pads
B30 and B31 flute pads have been industry standards for at least 50 years. Premium pads such as the yellow-skinned B26 and B38 offer something extra for higher-quality flutes or can simply dress up a student instrument.
Ferree’s flute pads fit Yamaha flutes without modification. If you purchased small-hole pads elsewhere, Ferree’s offers the N79Y punch for use with the N79 French Flute Open-Hole Pad Punch Set. The N79Y fits into the N79 set you already own and was originally listed at $14.50 plus shipping and handling.
If you do not already have the N79 set, it is pictured in the lower-left corner of page 28 of the 2001 green catalog.
These pads are made from high-quality wool and fish skin with a single-piece cardboard backing, just like the conventional pads used by instrument manufacturers. The cardboard helps keep the wool flat, while the fish skin creates the seal.
Nothing too difficult so far, right?
Woven Felt and Needle Felt Pads
The pads discussed above represent the conventional flute pads currently available, with the exception of the special-purpose B29 pads discussed later.
The standard pad constructions include:
- B30: woven felt with white skin
- B38: woven felt with yellow skin
- B26: needle felt with yellow skin
- B31: needle felt with white skin
Choosing woven or needle felt is generally a matter of the repair technician’s preference. Pad color may also be selected according to the customer’s request.
Manufacturers commonly use woven felt pads because their installation does not require quite as much precision. Repair technicians working on professional instruments, school instruments or store rental programs often prefer needle felt pads because they hold adjustments longer. They also tend to match previously installed woven felt pads after those pads have compacted through use.
Wrinkles, Pad Alignment and Attack Angle
When installing a pad, hold the washer so the skin does not develop swirls.
Starburst-style wrinkles are usually acceptable. If they become severe, investigate the attack angle between the key cup and tone hole. You may need to bend the key with the E100 and then change the washer arrangement to reduce the wrinkles.
Keys often must be bent as part of the adjustment process.
If the flute was poorly designed or its design was badly executed, the hinge rod may be in the wrong location or the pad arm may be too long or too short. In that situation, there may be little you can do to correct the underlying geometry.
Bring the assembly as close as possible while considering:
- Whether more or fewer spacer washers are needed
- Whether the pad is centered
- Whether the key appears aligned with the surrounding keys
- Whether the pad meets the tone hole evenly
Some technicians prefer to call this process “straightening” instead of “bending.” Sometimes a key simply needs to be bent. There is no reason to argue over the terminology.
Duplicating a Correct Existing Setup
If the flute is already in good mechanical condition and only needs pads, much of the difficult work has already been completed.
Use dial calipers, such as the G5A, which are calibrated in thousandths of an inch, to measure and duplicate the total pad and spacer thickness. This works only if the previous setup was correct, which can be determined through the same pre-inspection process discussed in the saxophone pad section.
Many repair technicians use this method because it can save several hours.
Flutes have the additional concern of pad retention. Too many spacer washers can distort a pad when the retaining screw is tightened. On an open-hole pad, too many spacers may prevent the grommet from holding the pad securely.
Carefully examine the angle of attack to determine which way the key should be bent to avoid these problems. The goal is a flat pad that contacts the tone hole evenly every time.
B29 Pads for Older Gemeinhardt Flutes
The B29 is a special, thinner woven felt pad designed for older Gemeinhardt flutes with straight, non-rolled tone holes and metal washers in the backs of the pad cups.
I usually remove those metal washers and build the assembly to the correct thickness using a conventional needle felt pad and paper spacer washers. If everything works correctly, you may not need to add anything else.
The measurements work as follows:
- B29 pad thickness: .098 inch
- Original metal washer thickness: .016 inch
- Combined thickness: .114 inch
That .114-inch total equals the standard thickness of B26, B30, B31 and B38 pads.
Some people believe removing the metal washers produces faster key action because the pad cup assembly becomes slightly lighter. I do not believe the player could detect the difference. I remove them because it makes the flute easier to service the next time.
If you are restoring a flute and want to preserve its original construction, leave the metal washers in place, install the thinner B29 pads and proceed normally. Everything should work properly.
For reference, the original washers had:
- A .180-inch or 4.57 mm center hole for screw-retained pad cups
- A .405-inch or 10.28 mm center hole for open-hole French-style pad cups
You can use the .405-inch washers for all the pads if you prefer. This avoids maintaining two inventories for instruments using this approximately 50-year-old design.
Ferree’s supplies these washers as part A110. They are .016 inch or .4 mm thick and are available from 16 mm through 18.5 mm in .5 mm increments.
This system was originally used because manufacturers were working with straight-cut tone holes and extremely thin pads that were difficult to flatten and keep flat. Those pads often looked like potato chips. The metal backing system worked for that design for a while.
Some newer instruments are again being built with very thin pads, and the old problems are beginning to reappear. Apparently, not everyone remembers the “good old days.”
Modern pads are much higher in quality. A slightly thicker cardboard backing has proven more effective, and Gemeinhardt eventually recognized that as well.
Alternative Flute Pad Systems
Several other pad systems have been introduced in recent years to make flute repair supposedly “better.”
One technology is a little like putting disc brakes on a horse. Another is like trading a new automobile for a buggy without the horse.
Does anyone really want to return to making pads by hand? That would be a major step backward.
If a flute repad costs $950, how much of that price is for manufacturing the pads rather than repairing the instrument? Is it a homemade $300 set of pads combined with a $650 repad?
I do not know many technicians who are so short of repair work that they want to begin making crafts like a flea-market vendor, especially after paying someone hundreds of dollars to teach them how.
A professionally produced pad should consistently outperform a homemade pad. Production pads are more uniform, more consistent and made by people who manufacture pads for a living.
The pads should be the least of your problems. Let’s keep it that way.
How Long Should Flute Pads Last?
Properly installed conventional flute pads can last five to ten years or longer if they are not damaged.
We once included two years of free service with every repad or overhaul. Those instruments generally stayed out of the shop unless they were damaged.
We would tell customers, “Bring it back in about a year, even if you do not think it needs anything.”
That coverage applied to normal wear and tear, not misuse or abuse, as determined by the repair technician. We never had a problem with the policy.
Flute Pad Installation
When the Original Pads Have Been Removed
This is where many flute repairs become unnecessarily confusing. There is so much questionable information about installing flute pads that the process can seem much more complicated than it really is.
Sometimes a parent tries to save money by removing the pads before bringing in the flute. They believe they are helping by reducing the technician’s labor.
Instead, they have removed the original thickness and placement references. Losing that index can add approximately one and a half to two hours to the repair.
Charge for the additional two hours and explain why. If the customer takes the instrument somewhere else, another technician will lose the value of those two hours unless that technician also charges for the extra work.
Establishing the Correct Pad Height
When the original index is gone, begin by installing a pad in the cup with its screw or grommet.
Install the key on the body and check the contact pressure at the back of the pad. In most cases, the pad will initially be light at the back or may not contact the tone hole there at all.
Estimate the missing thickness. Remove the key from the body, remove the pad from the cup and add the required thickness with full paper spacer washers.
Reinstall the pad, reinstall the key and check the contact again.
Do not take shortcuts. They do not save time. You may need to repeat this process once or twice.
If the flute has not been damaged, the same pad and spacer combination will probably work for other keys mounted in a similar way. Duplicate the measurement when installing pads in each related group, then check every pad individually.
These groups include:
- Upper stack
- Lower stack
- G key
- G-sharp key
- Foot joint
The keys within each group share similar hinge points, which is why one successful measurement can often guide the others.
If a pad remains light at the back, remove the key and add more thickness.
If the pad becomes light at the front, remove a small amount of thickness until the pressure is equal around the tone hole. The pad must be level all the way around.
Check the Lower-Stack Post
Always inspect the lower-stack post.
If the pads become progressively worse along the lower stack, the post may need to be returned to its original position.
If the post is bent toward the tone holes, the pads will become progressively lighter at the back. If the post is bent away from the tone holes, the pads will become progressively heavier at the back. They may also become visibly off-center.
Do not use centering as your only guide. Some flute pads are not perfectly centered even when the mechanism is correct.
The pads must be level or the flute will not play properly.
Avoid Unnecessary Bending and Partial Washers
Do not immediately begin bending the fronts of the pad cups downward.
The best approach is to avoid bending keys when the problem can be corrected properly without doing so.
Most importantly, do not use partial washers.
One school of thought recommends using halves or smaller pieces of spacer washers. That method may have some merit in certain circumstances, but two highly respected repair technicians, George Jameson and Dick Rusch, used to say:
A half washer creates two leaks.
They would go crazy if they saw all the washer “confetti” sometimes used to level pads today.
How Pad Cups and Keys Actually Move
Pad cups are coined under tons of pressure and are thick in proportion to their size. In practical terms, the cups themselves do not bend easily and usually do not distort under normal conditions.
To level a pad from side to side, you can slightly twist the key arm. This is essentially what happens when the E61 Flute Pad Gauge or Leveling Tool is placed beneath one side of the pad and pressure is applied to the opposite side.
You can also lower the front of the pad cup by placing the E61 beneath the back of the pad and pressing the front downward. This may slightly bend the edge of the pad cup, but usually not enough to be noticeable.
A key may need to be bent to correct previous damage or an earlier improper adjustment. In some cases, the heavier arm connecting the hinge tube to the pad cup must be bent.
Why? Because pad screws are only so long. The same limitation applies to the grommets used on open-hole French-style flutes.
If a pad is too tight at the back, remove some spacer washers and reduce the total thickness.
If there are no spacers to remove, use the E100 to correct the key geometry. This takes more time, but accuracy matters, and the additional work can be included in the repair price.
If the pad is too light at the back, add spacers, but only to the point that the screw or grommet can still retain the pad properly.
Check Post Position Before Making Corrections
Whenever something does not look right, quickly check the post positions before changing the pad setup.
There is a small argument in favor of using plastic spacers instead of paper spacers, but it is not significant enough to create much concern.
How much humidity can a .010-inch piece of paper absorb when it is clamped beneath a sealed .114-inch pad that is press-fitted into the cup? What about every other component in the instrument?
A variation of one or two thousandths of an inch is not worth worrying about in this situation. Everything is relative.
Flat Tone Holes, Flat Cups and Flat Pads
A properly manufactured tone hole should be flat. A slightly uneven tone hole can be corrected with the E98 Tone Hole Leveling Tool.
The pad cup should also be flat.
The pad is usually the least variable part of the assembly and should remain flat when using the standard .114-inch pads discussed above. Their cardboard backing is thick enough to maintain the necessary shape.
If the total assembly needs to measure .123 inch, add a .009-inch, .010-inch or .011-inch washer.
You can always bend the front of the pad cup downward slightly. Starting a little heavy may prevent you from having to remove the pad again.
There is no room for partial washers in this method. They are difficult to position precisely and, in the larger repair process, are usually a waste of time.
This may be called “old school,” but it worked in the past, it works today and there is no reason to replace a method that is not broken.
Using partial washers can leave you chasing problems that do not need to exist. Level the complete pad over the tone hole and you are almost finished.
Adjusting the Flute
At this point, you have installed a pad. Somewhere in the process, the mechanism must also be adjusted.
The adjustment screws found on properly designed flutes function in only one direction, not two.
These time-saving, wear-reducing screws control the downward movement of the keys. After all bending and pad leveling have been completed, use the screws as stops so the connected pads reach the tone holes simultaneously in the down position.
The upward position is adjusted by either:
- Bending the key tail upward or downward
- Removing cork from beneath the key foot or adding more cork
Choose the method that works best for the instrument and situation.
Yes, I have installed adjustment screws in a Haynes flute. They can save a great deal of time and frustration.
Using light pressure, allow each pad to gently kiss its tone hole. Confirm that the contact is even around the entire circumference.
Make sure every connected key combination closes at the same time. Completely adjust the flute at this stage.
Check the key openings for the correct height. Recheck the bridge key and the thumb key B and B-flat adjustments.
Checking the Pads Before Seating
You may be thinking, “You have not ironed or seated the pads yet.”
That is part of the time-saving process.
I have never ironed pads because I use a feeler gauge. If you prefer to iron pads or use a leak light, do so after the pads have been installed at the correct height.
I have nothing against using a light. I am color-blind and cannot reliably see with one, so I use a feeler to compare contact pressure around the pad.
Do not use “elephant fingers” when comparing pressure.
The pads will be seated, but not yet. If they were installed correctly, minor wrinkles should not matter. At this point, concentrate on making every pad level.
Level means level, not almost level.
The flute should nearly play at this stage. Sometimes it already will.
Seating the Pads
Applying Water
Once every pad is installed, leveled and adjusted, place approximately one drop of water on each pad using the looped end of the E34 Blue Pad Iron.
Dip the loop into the water, then spread the water across the pad as it is applied.
I use distilled water because it should contain no impurities. Softened tap water or tap water with a low mineral content can also work.
Water with a high mineral content may leave calcium, iron, rust-producing material or other deposits on the pad’s surface. These impurities could interfere with seating or contribute to premature wear.
The choice is yours.
Use G26 or G82 Spring Clips to hold the pads closed during the seating process.
Preparing and Organizing the Spring Clips
Technicians who are new to this process may get better results with G82 clips because their tension is easier to adjust.
Begin at the top of the flute and work downward.
The clips have adjustable tension, so they should be prepared and arranged before installation. Mine are stored on a four-inch hook screwed into the edge of my bench. They are installed and removed in the same order every time.
A few clips are bent or shortened to clear the G-sharp key or work around the thumb keys. Otherwise, they remain fairly standard.
Most importantly, every clip is tensioned to perform its specific job.
Controlling Clip Pressure
Unfingered pads should receive less clip pressure because they should not develop deeper seats than the surrounding fingered keys.
For example, the upper pad of the lower stack does not technically require a clip. I install one anyway, but with lighter pressure.
If all four lower-stack pads are correctly leveled and adjusted, the remaining three pads will close to the same height during seating. The unfingered upper pad acts as a stop and determines the proper seat depth.
The same principle applies to:
- A and B-flat
- C and C-sharp
- The bridge mechanism
Use very little clip tension on pads that the player does not press directly, particularly when those pads are closed by another key or held closed by a spring.
I still install clips on the trill keys, low D-sharp, both G keys and the upper C key. This may partly be habit, but it also protects the process if a spring fails. Besides, the upper C is sprung open.
Clarinet Pads for the Upper C and Trill Keys
Use three B11 or B21 clarinet pads in the upper C and trill key cups. Their double-skin construction more closely matches the rest of the pad set.
If thin flute pads are used in these cups, the additional adhesive required behind them may ooze from beneath the pads.
The thicker cardboard backing of the clarinet pads maintains the proper pad projection, or reveal, from the cup. This produces a cleaner and more trouble-free installation.
Heating and Setting the Pads
Place the clipped flute in a preheated X100 Pad Oven, or an X100A 220-volt oven in Europe.
Heat the instrument for six minutes at 212 degrees Fahrenheit. Use a loud bell timer so the heating cycle is not forgotten.
Remove the flute and allow it to rest until it cools.
If you are in a hurry, compressed air can be directed through the body tube to cool it. I prefer to let it sit naturally while I work on something else.
Deep pad seats do not guarantee an airtight seal. In many cases, a deep seat creates a false sense of security. It can make the instrument more difficult for the technician to regulate and more difficult for the player to use.
An unnecessarily deep seat can slow both key action and key response.
Removing the Clips and Completing the Repair
Once the flute is cool to the touch, remove the spring clips from the bottom upward.
Return each clip to the hook in the exact reverse order so the set remains arranged correctly for the next repair.
Usually, no further adjustment is needed or wanted. Every part of the pad and tone-hole relationship has just been heated and formed together. It would be difficult to bring the assembly any closer.
Check the instrument anyway. A cork may have expanded during heating or another small regulation may have changed.
If you do not have a pad oven, some technicians use a conventional electric oven. However, household ovens may be inaccurate and can vary by as much as 50 degrees. The temperature may become excessive even when the control is set correctly.
If the flute is slightly out of adjustment after cooling, regulate it using your normal method and complete the repair.
