Harmonica mouth-organ

Inside the Chromatic Harmonica
A Lesson in Chrom Anatomy.

Essentially a chromatic harmonica is made up of the following components.

• Comb
• Reedplates
• Reeds
• Windsavers/Valves
• Spring
• Slide Assembly
• Mouthpiece
• Covers
• Cover Struts

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Comb

This makes up the body of the instrument and what everything else is attached to. They are typically made of wood or some form of plastic. More expensive or custom models may have the comb made from aluminium, stainless steel or even titanium.
The comb is specifically shaped for the type of reedplates and mouthpiece assembly used, and rarely interchangable with other models or makes of chromatic harmonicas without an amount of machining.
Each comb cell or hole shares two reeds, draw & blow, the cell is shaped specifically for those two reeds generally to optimise the flow of air that passes them.
Combs may be nailed into; they may have tapped threads into the material for screws; possibly holes drilled through for bolts to go through and attach to a theaded plate or bolt; or have threaded inserts fixed into the comb which give a harder wearing thread for bolts or screws to attach to.
Wood combs can crack, shrink, swell or warp if exposed to excessive moisture, heat or cold, and are easy to dent or damage which can reduce airtightness. Other materials are generally more durable and therefore desirable in my opinion.
There is an ongoing debate between harmonica players as to the effect of the comb on the overall tone of the instrument. However no satisfactory conclusion has been drawn either way.

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Reedplates

Typically any chromatic harmonica has two reedplates, one on each side of the comb. The reeds are aligned to fit two into each comb cell, one draw, one blow. For the majority reeds there is a windsaver attached to the other side of the reed hole. Reedplates are made normally made of brass. Some chromatics have the brass reedplates plated in chrome or silver to reduce corrosion or reaction to other metals used on the instrument. It is important to take care not to bend or twist reedplates as this will reduce airtightness.

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Reeds

Reeds are essentially what makes a harmonica what it is, each reed produces a tone when air is passed over it. There are two reeds per comb cell, one for blow, one for draw for each hole on the harmonica. Reeds are attached to reedplates, typically riveted. Reeds should be made of the same material as the reedplate (usually brass), otherwise it will react with the reedplate and corrode quickly.
A reed is described as having a root where it is attached to the reedplate, and a tip which is free to vibrate. Reeds are delicate and easily damaged, so take great care with them especially when handling reedplates. The hole that the reed sits over is designed to be a very tight fit for the reed without any point of contact beyond the root of the reed, this is to reduce the amount of airflow to make the reed work. If the reed catches any edges of the hole it will not play properly, so if the reed is not set in its hole properly or if there is any obstruction or burr sticking out from the reed or the edge of the reed hole this will cause problems.
Reeds are tuned to a set pitch which they are designed to sound when they vibrate. This can be purposely altered in a number of ways, but retuning is usually done for a specific purpose and not something that is done more than a few times in the life of a reed if ever. When a reed eventually becomes fatigued it will slowly and almost imperceptually lower in tone until it is off-key. It can be retuned, but will soon break, at this time it is prudent to either replace the reed or the reedplate.

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Windsavers
AKA Valves AKA Pallettes AKA &%^#(@-things!!

As its name suggests a windsaver conserves the amount of wind or breath required to play a note on the harmonica. They are set up on the opposite side of a reed hole to the reed so when the opposite reed in the hole is being played, the windsaver is pushed shut over the hole to stop air escaping through it. The valve covering the reed hole of a reed being played is pushed out of the way by the air that is playing the reed. Without windsavers a larger amount of air is required to make reeds sound, as a result on some chromatics both reeds in the cell may sound. Windsavers are a neccessary evil.
Windsavers or valves are normally made of plastic, but can be made out of anything. Valves are glued to the opposite side of reedhole to a reed at the same as where the root of the reed is attached. They can be constructed of two flaps: The bottom flap is soft designed to seal the hole and be pushed out of the way when its reed is being played, the top flap is stiff & springy, designed to push the bottom flap back to the reedplate.
Also they can be made up of a single flap made of two components, the underside is soft which is firmly adhered to the topside is stiff & springy.
Single flap windsavers are less prone to problems simply because they are a single component and cannot adhere to itself, also they are stronger and will probably last a little longer than the two flap variety.
Valves are the cause of most problems in the daily life of a chromatic harmonica player:

• If the windsaver of a reed comes back to rest before the reed stops vibrating it causes a buzz at the end of each note.
• If a valve does not sit flatly on the reedplate, it may not be able to form a proper seal when blocking a reedhole and vibrates with the air creating a buzz.
• A windsaver can stick to the reedplate either due to residue (dirt, saliva, etc) around the reed hole and on the windsaver or due to moisture effectively causing an airtight seal between the two components. This causes a symptom known as popping where initially when a hole is played the note does not play or is muted, then as more breath is applied it suddenly pops and sounds properly.
• A valve can stick to the cover or more rarely to the base of the comb, again due to either residue or moisture. This renders the windsaver useless until released with a pin or penknife blade tip.
• Windsavers that are made of two seperate flaps can have the flaps stick together which stops it behaving properly either causing it to buzz and/or holds the windsaver away from the hole so it doesn't work properly.

Moisture, condensation, dirt and residue are the enemy of the windsaver. Windsavers should be kept clean, sit flat and align with the reedhole without gaps around the edges.

There is a myth that windsavers inhibit the bending of notes. This is not true, if anything they help bending of notes, the problem is a different technique is required due to the design of chromatic harmonicas compared to diatonica harmonicas, also the average chromatic harmonica is by design usually leakier than a diatonic harmonica. Although this is not always true.

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Spring

The spring's purpose is to push the harmonica slide out.
The majority of chromatic harmonica springs are installed inside the comb and made of strong flexible metal. They are generally hairpin shaped and held in place to the comb with a pin or dowel inserted at the apex of the spring. One spring arm is longer than the other and this extends out from the comb just far enough to hook through a small hole in the slide.
Early chromatic harmonicas had an external spring that was a long rectangular shape and they arced from the right side of the comb and attached to the slide, or vice versa. These are said to have a smoother action than the internal springs of today, they are also a lot easier to access and work with than internal springs. However the spring is exposed and vunerable to damage and some people find them displeasing to the eye.

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Slide Assembly

By design when you move the slide back and forth it exposes alternate sets of holes on the comb, this is how the two sets of reed tunings are seperated and selected.
Slide assemblies need to have close tolerances with minimal gaps to increase airtightness. Slide assemblies that have close tolerances tend to stick more readily which is remedied by regular cleaning, and dripping water through the slide assembly before and after playing, as described above. Slide assemblies that have more open tolerances don't tend to stick much, but makes for leaky instrument.
In most cases the chromatic harmonica slide is a long thin rectangular strip of metal with regular holes punched into the main body, it has a tang at one end with a button attached, and a small hole drilled to fit the slide spring. There are also one or two oval holes, for the mouthpiece screws to go through. There is usually a backing plate that goes between the slide and the front of the comb. It has holes punched out that match the cells on the comb.
Some chromatic harmonica slide assemblies have a flange sitting between the mouthpiece and slide. It forms a channel between itself and the backing plate for the slide to operate. All the Hohner wood comb 12 hole chromatics have this assembly. Other chromatic harmonicas have the flange integrated into the back of the mouthpiece, such as the Hohner 16 hole models. A few harmonica designs have a completely different mechanism for the slide such as the CX12 and the discontinued Hohner CBH 2016.

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Mouthpiece

Usually a long thick strip of metal with holes for playing through, and a hole at each end where it is attached to the comb. Some mouthpieces are designed to be integrated with the slide mechanism and encompass the slide and connect with the backing plate.
With any mouthpiece it is important it is smooth and friendly to the mouth & lips. Sharp edges, burrs and certain metal reactions and/or allergies can be the cause of discomfort, making the difference between a great instrument to play and an unpleasant experience discouraging the player. There are chromatic harmonicas made with plastic mouthpieces, also a few designs have the mouthpiece as an integral part of the harmonica cover in a single component to improve airtightness.

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Covers

The chromatic harmonica covers form a protective shield around the reeds and valves primarily to protect them, and direct the sound out the rear of the instrument.
Most covers are two plates of metal, one for the top and one for the bottom of the instrument and are attached to the comb with screws or nuts & bolts. Covers are typically made of stainless steel, plastic, or brass plated with: nickel, chrome, silver or gold. Chrome is hard wearing, as is nickel, silver is slick in the mouth and sticks to fingers, gold is soft and wears off easily. The front of the covers must fit tightly and form a proper seal at the front of the instrument by the mouthpiece to improve airtightness, to reduce vibration and in some cases to avoid cutting the players lips. Sometimes covers are a single component integrated with the mouthpiece like the Hohner CX12.

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Covers Struts

Most chromatic harmonica covers need some form of support so they don't buckle. This support usually comes in the form of:

• Four small metallic struts, two for each cover that are installed into two holes the back of the exposed reedplate. Most but not all of Hohner chromatics use this method.
• Two metal posts going through the comb like Hering chromatics.
• Cover struts an intrinsic part of the comb design like Hohner CX12s.
• Or the back of the cover is designed to support itself, resting on the reedplate or comb at the back of the instrument, like the Huang #1248.

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That is basically what a chromatic harmonica is composed of. However there are a number of specific differences in design from one make or model to the next.

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Basic Tools
What tools are required to work on your chromatic harmonica.

To completely disassemble/reassemble your harmonica, and to be able to repair/replace windsavers you will need the following tools

• Small pocket/pen knife or Craft razor blades Essential and useful in so many ways. Primarily for fixing or removing windsavers and removing reedplates from wood combs.
• Smooth flat working surface preferably hard plastic, but wood will do and make sure it has a clean edge. The edge is so you can hang the button edge over the end without causing the slide to bend. A flat surface is very useful for checking and straighting parts like the slide assembly and mouthpiece.
• Tight fitting Screwdrivers. Purchase a set of jewelers set of screwdrivers from the hardware store, they are inexpensive and will save a lot of grief later on. They have a swiveling head which makes it easy to keep them in place while turning. In any case it is important each screwdriver fit tightly into any screw its used on avoiding any damage to the screw head and to reduce the chance of slipping.
• Small Hammer for wood comb harmonicas to knock nails back in.
• Windsaver Glue such as all purpose craft glue or similar. For gluing windsavers onto reedplates.
• Small flat faced curved nose Pliers (optional) For holding small parts while working on them.

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Repairing a Cracked Wood Comb

Wood combs can warp and crack. A typical symptom of a cracked comb is two neigbouring notes become leaky and play at the same time.
This is how to fix it:

• Remove the mouthpiece and slide assembly, leave the covers, reedplates and comb assembled - this will hold the cracked comb in position.
• Use a small amount of araldite epoxy clear adhesive on the end of a toothpick or small plastic spatula and smear along the crack in the comb chamber - use enough to hold the comb in position once its set.
  NB araldite is a range of two part epoxy adhesives sold by various manufacturers around the globe, any araldite product appropriate for general use listing wood as one of the materials its intended for will work.
• When it has set hard you can remove the covers and reedplates.
• The comb should be in one piece because of the araldite, but be gentle. Now you can finish filling the crack in with more araldite, smearing it into the crack and thinly over the surface.
• Wait for the araldite to degas and set.
• You may need to give the comb a light sanding to remove anything sitting proud. Ideally use a block of marble or 1/4" thick plate glass with moderate grain wet & dry or sandpaper taped down firmly or adhered to it.
• Reassemble and play.

Instructions for nailed wood comb chromatic harmonica disassembly and reassembly.

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Replacing a Wood Comb

You can purchase a new replacement comb from Hohner or HarpOnline.de and install it yourself.

Put the new comb front face down (where the mouthpiece goes) on a flat surface such as a segment of polished Marble or better yet 1/4" thick plate glass. Start with one reedplate getting it so its flush at the front:
Hold the reedplate down with your fingers at each end and make sure all the notes are playing. It doesn't matter at this point if they are slightly leaky. If notes are not playing shift the reedplate around gently until everything is working properly.
Having found the ideal location, keep everything in place with one hand while pushing three nails in, one at each front corner and one center back. You will need to experiment to find the best way to go about this - but the principle is simple enough.
Having done this double check that all the notes are playing, and check that the front face of the reedplate is flush with the front face of the comb (using Marble or 1/4" thick plate glass). If it isn't, fill in the three nail holes with the tip of toothpicks, snap them off, and gently press the filler flush with the comb surface using a small hammer or 2mm punch and start again.

Having succeeded installing the first reedplate, you will now have enough experience to do the other reedplate more efficiently.
Once both reedplates are installed and the notes are all working, tap in the rest of the nails. For this I use a 2mm punch and a small hammer.

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If you cannot find a way to install reedplates properly with all the notes working, it is very likely that the wood comb you have bought has swollen. Its simple enough to visually check this by lining the reedplate up with the comb and looking through the front of the chambers. There are two ways of fixing this:
1. shave all the tines down to make them thinner, you may need to do the same to the outside walls of hole 1 & 12's chambers.
2. throw the comb away and find another solution.

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You may want to give the front face of the comb/reedplates a very light sanding:
Tape or adhere 400 or finer grit sandpaper or wet and dry of dimensions at least 3" x 8" to a very flat surface, such as a piece of marble or 1/4" thick plate glass.
NB: [1]Remove any stickers that you may find on the back of the abrasive paper. I am talking from experience.
NB: [2]If the surface you adhere the abrasive to is not guaranteed flat there is no point in doing this as you'll only ruin the mating surface for the mouthpiece and slide assembly.
Place the front of the comb/reedplate assembly flat onto the abrasive paper at one end, use both hands to gently grip either end of the back of the comb /reedplate assembly and keeping it flat and even move it to the other end of the abrasive paper, pick it up, turn it around and repeat one more time only.

Once you have assembled the reedplates to the new comb you will need to drill the spring pin hole. Use a drill bit that just fits through the reedplate spring pin holes (3mm). A hand drill is preferable to a power drill if you are inexperienced at this. Drill half way into the comb from the top reedplate, flip the assembly over and do the same again. Install the spring, the spring pin and finish assembling your instrument.

This articl eis taken from http://www.angelfire.com/music/HarpOn/