17549072_10209195776072447_187691784_o-300x170 Step-By-Step Instructions On Building a Kettlewell Frictionless Mouthpiece

(Photo-this is art of an early version of the Kettlewell Frictionless Mouthpiece, designed by the DeQuelery Instrument Company in Holland. Note this drawing shows the mouthpiece only, not the comb and covers. This design was set aside, and replaced by the simpler SLEEVE type Kettlewell Frictionless Mouthpiece described below; built on a conventional mouthpiece having minor modifications, providing a very stable platform. Note this drawing has the 1 hole slider preferred by Mr. Kettlewell, as it allows a relaxed pucker embouchure. Many players may prefer a 5 hole slider.)

As this design was donated to the Public Domain as a public service by Mr. Kettlewell, anyone may use the ideas below to develop a Kettlewell Frictionless Mouthpiece.

Mr. Kettlewell’s sole request is that the mouthpiece be named….Kettlewell Frictionless Mouthpiece by (your entity)


  • Player’s lips stay stationary on SLIDER, the SLIDER articulates back and forth on the BASE.
  • Lack of need to lubricate lips to effect movement to new note hole positions means that movements to new note hole positions are easier, and faster, which means new styles of play can be created.
  • As the lips stay stationary on the SLIDER, the question of what shape of SLIDER will be most ergonomic in play. Perhaps a cast of lips in plaster would help in considerations of same.


  • These instructions are for fitting of a Kettlewell Frictionless Mouthpiece to a standard chromatic harmonica mouthpiece. This is the simplest type of frictionless mouthpiece which can be made. It is built on an existing mouthpiece requiring only limited modification, and of course this means the player may opt to play their harp with the Kettlewell Frictionless Mouthpiece, or the stock mouthpiece as they choose.



Placing a stock frictionless mouthpiece on its comb with (reed plates and slide both removed for this cut) have a machinist take off from 4 to 10 10,000ths of an inch from the top of the stock trapezoidal mouthpiece surface…until the top surface of the trapezoidal mouthpiece is absolutely flat, and the hole top edges crisp. This provides an optimal top surface for the SLIDER.

Cut a channel of 1mm in depth and height running lengthwise at the bottom of the mouthpiece, the lower lip of the SLIDER will run in these channels to keep the Slider on the harp. The cut edge should be smoothed so it cannot cut a lip should the player drop their lips to the BASE somehow in play.

Note that the smoothing of the mouthpiece top face MUST be done with the mouthpiece attached to the body or comb/reedplate assembly of the instrument, or the correct alignment of parts for the frictionless mouthpiece to function properly will not occur. The mouthpiece should not be shaped off the instrument, but instead, on.


The slider fits on top of the BASE, and runs left and right on the BASE. It is the same shape to the lips as a stock mouthpiece in play.

The SLIDER is from 2 to 3mm thick, cut by CNC tool and die from a block of solid silver, and is made with 1 or 5 holes depending on player preference. Players using pucker embouchure will likely prefer the 1 hole, players using tongue block/ corner switching, the 5 hole. The unit can be sold including both types.


The thickness of the slider is 2 to 3 mm, depending on stability requirements as your designer/engineers see fit.

The slider should be cut from a block of silver.

The outer edges of the SLIDER feel identical to the stock harp’s to the player’s lips.

However, the sides of the underside of the SLIDER are cut to provide 8/10,000ths of an inch slack to the sides of the BASE, or more, which will allow ease of movement of the SLIDER even with saliva buildup. It may even wiggle a little bit when turned left and right.

The hole created in the 1 hole SLIDER is left sharp at bottom for perfect interface with the top surface of the BASE, but the top of the hole feels the same to the player’s lips as a stock mouthpiece hole…i.e. smoothed.

CRITICAL!!! The under surface of the SLIDER (which will interface with the top surface of the BASE) must be totally flat…as this is the critical interface of parts to ensure air tightness in play.

Of course the comb must be metal, aluminum or brass, as metal combs are far more stable torsionally, and this torsional stability affects airtightness of the instrument.

A single hole slider should measure about 1 ¾” in length, allowing the lips to sit relaxed on the slider in play, but provide the effect of pucker embouchure.

The slider is kept from sliding off the harmonica end to end by small round post top screws placed in the Lower or Base (in this case the smoothed mouthpiece) and of course the Slider or Upper hits these screws as the Slider approaches the end of the harmonica.

A small inward lip is cut into the lower insider portion of the SLIDER which runs in the channel previously cut in the Base. This lip should be 9/10,000ths of an inch less in height than the channel, and 3/10,000ths less deep than the channel cut, so the lip does not impinge on frictionless movement of the SLIDER to the BASE.

Recap: Note that the SLIDER can move easily left and right on the BASE. The lip of the SLIDER runs in the channel of the BASE, and the small post screw heads keep the SLIDER from coming off in play. The critical interface is the top of the mouthpiece, or BASE, to the underside of the Upper or Slider where the single hole is cut on a 1 hole slider.

Again….the sole interface which is critical in manufacture to ensure airtightness is the absolute precision fit of the underside surface of the top of the SLIDER (where hole is) to the topmost surface of the mouthpiece, or BASE. As long as reed to reedplate tolerance is precision and close, and windsavers are attached, the instrument will be airtight.

Fitting a standard mouthpiece is easy…just replace the modified Lower with a standard mouthpiece.

There’s a little slack of the SLIDER to the BASE side to side. This is done so that saliva buildup will not impinge on ease of movement.

Note that replating of the BASE after shaping by the machinist is unnecessary, the lips of the player do not touch the BASE.

The unit is designed to be used with just a thin film of slide oil between SLIDER and BASE, easily applied to the BASE with SLIDER still on.

Note that the above design allows the user to remove the SLIDER for replacement by removing either of the two post head screws in the BASE at either end. One could also swap one Upper out for another design model.

In time the harmonica can be made with extra length to the left and right of the last holes on the mouthpiece, provide a bit larger area for the lips of the player to rest on a longer Slider, but this design will work nicely for now.

In the future, other SLIDER materials and upper surface designs perhaps more ergonomic to the lips can be tested. They key point here is that historically, the shape of the mouthpiece was determined by the fact that the player’s lips had to move left and right on it, lubricated by saliva. As the player’s lips on a Kettlewell Frictionless Mouthpiece do not move, the actual shape of the Upper can be more ergonomic. Of course, some extension into the mouth is needed to effect tongue taps, but the shape can in time be more comfortable to the lip than historical shaping of mouthpieces.


Various materials may also be developed for the Upper, including Delrin, which offers the advantages of low cost, easy replacement, and quietness in play, and slight flexibility which may aid airtightness. However, SOLID SILVER is the preferred Upper material…which must be cut by CNC from a solid block of silver to ensure absolute stability of shape.


Same as above except that the length of the SLIDER is expanded to allow for 5 holes.

Of course, Mr. Kettlewell plays using a custom button of his design, and you may want to create this as well, you will find photos of his button on the Facebook Group CHROMATIC HARMONICA CUSTOMIZATION.


The greatest challenge is to resolve two conflicting design characteristics…the need for easy and smooth articulation and movement of the UPPER upon the LOWER…….and the need for a very airtight harp.

This challenge is magnified by the reality that the torque applied to the mouthpiece screws which attach the mouthpiece to body, can very tight or not so tight…and this will affect the curvature of the mouthpiece LOWER somewhat. When the screws holding the LOWER to the body of the harp are very tight, the LOWER takes one physical shape…..and when the screws are a bit looser, the LOWER will have a more relaxed shape.

ABS and acrylic combs are NOT RECOMMENDED for the Kettlewell Frictionless Mouthpiece, as they deform a bit as mouthpiece screws are tightened…enough to possibly affect perfect airtightness.

The most stable design is the same as the Seydel Saxony, using a MODIFIED H BAR (the construction would be comb/slide/Modified H Bar, then UPPER) rigidity of the assembly can be accomplished. The H Bar would be made of steel.

The use of a polymer UPPER made of Delrin, would also allow the UPPER to change shape by 3% to allow shaping to the LOWER.

Nano particle coating of articulating surfaces may also be considered, or the use of slide oil used to improve airtightness.

– Another design challenge is that the instrument is played currently with two embouchures: the PUCKER, where the lips take on the shape as when whistling,…and the TONGUE BLOCK: when the lip opening created spans from 3 to 5 holes, with the tongue “blocking” the holes one does not desire to activate with breath.

If an UPPER has 5 holes, to allow the player to utilize the TONGUE BLOCK embouchure, then as the player approaches the Right or the Left end of the instrument, the player will have to move on the UPPER to get to those final holes.

The solution is to allow the upper to extend BEYOND the lower sufficient to allow activation of the desired hole without the player having to move to a new position on the UPPER.

Here, the player must be careful, as we do not want a player’s left hand to be hit by the UPPER as it extends beyond the edge of the body of the harmonica.

By making the harmonica body slightly longer than normal, we can address this to some degree, or instruct players that they will have to shift position on the UPPER to reach the far notes L and R.

This is a challenge.

– It is also possible to create a harness which holds a microphone in an outer cage of the harp, so that the microphone position automatically stays opposite the player’s hole position.

– Another issue to consider is whether wear will affect airtightness of the instrument over time of play.

– The Upper and Lower must be made such that if the player slips off the UPPER, they do not cut their lips on the LOWER. Safety issue.

– As with any new design, there will be plusses and challenges.

MARKETING PLUSSES of the Kettlewell Frictionless Mouthpiece:

– INSTRUMENT PLAYS DRIER AND NEEDS LESS MAINTENANCE…Because you do not need to use saliva to play the harp and articulate between notes, the instrument will stay much cleaner, longer, and require much less cleaning. As harmonicas are finicky to clean, this is a big plus.


– AIRTIGHT CONSTRUCTION means reeds activate with very little breath, so less tiring, better tone, and better control of soft notes.

– YOU DON’T HAVE TO CONTINUALLY APPLY SALIVA FOR MOVEMENT TO NOTES…put the harmonica on par with other professional instruments

. AIRTIGHT CONSTRUCTION means less air is needed to activate reeds, better tone, easier,

– VARIETY OF UPPER SLIDER SHAPES allow you to change the shape of your embouchure in practice and performance, lessening fatigue. Any position held all the time becomes tiring for your muscles.