Aluminium Comb for Super Chromonica 270

[Thisisme80]

Hello dear Meisters,
My Super Chromonica 270 broke following Newton's law of gravity. I disassembled the harp to arrive at its broken comb and realized that it had broken into two pieces. I taped the pieces together and took the assembly to a local machine shop and bought two billets of same size as the comb, one in pure aluminium and another in aluminium bronze. Now the friend at the machine shop says aluminium is easier to mill and produce a replica of the comb for its soft metallurgical properties. I plan to use it as my replacement comb. He also suggests that bronze may give a better sound quality because of its acoustic properties. Now I have a few questions for your good selves.

1. Am I considered sane in harmonica land for wishing to replace the pear wood comb with a metal comb? If yes then next questions make sense.
2. I have read in some threads that comb material does not matter. I still dare to put this question again that should I go for aluminium comb or bronze one?
3. What about my lungs? If I am drawing air out of metal combs, am I in for some serious damage? Do I need to sanitize the metals in some way?


Regards,
Prash

[HallelujahAL]

I don't know the answers to your questions - so I'll be following this thread closely.
AL

[Grizzly]

Hohner makes its Meisterklasse with an aluminum comb. Plain aluminum, without some sort of coating, may react with the brass reedplates, and cause the aluminum to powder. I'd suggest a thin coat of paste wax before assembly.

There were several stainless steel combs made a few years ago, and sold on a subscription basis, and are being used on 270s with great success. Combs have been made of different metals, woods and plastics for years. Some people think they hear a difference, others don't. Aluminum bronze may be a good experiment.

Tom

[Ray J]

My questions are.

1 - At what cost?

2 - Is it ecconomical?

3 -Why not buy a new Comb?

One question really.

Ray 

[kc_liaw]

yes.. metal comb did give different tone quality than wood comb. .. and the airtighness is much better if it is done percisely.

Alum is light but oxidation is a problem. until today we still don't know what is the health hazard of alum oxide. one of the solutions would be to  anodize (i.e. rapid oxidation ) or with dry powder coat w layer of paint then baked it until it melts down and sticks permanently .

bronze is considered as good alternative but it is heavy (compare to alum.) and its oxidation problem (appear in green color ) will come in time. solution is..  plated or electrolisis process it with silver... since you are getting alum. bronze .. so i guess anodize (i.e. rapid oxidation ) or dry powder coated with paint

take note anodized or powder coated with paint will only give you temporary protection.  it will peel off after sometime and then u hv to send back to factory to clean up and redo anodize paint again.

the ideal solution would be, replace with  a original wood comb that is cheap and easy. i heard some one has old stock or u may try harponline.

or get a used one from ebay, a decent 270 in ebay wont cost much. recently i just got one around USD10.

good luck and cheers.

[Philos]

Aluminium is highly reactive when in direct contact with the brass reed plates. I was interested to read a comment about the meisterclass harps having trouble with corrosion on the combs and a little surprised that hohner would mate these two materials without any form of protection on the aluminium. In the aircraft industry (pretty much all Airframes are made from aluminium) there are a few choices on how to get around this problem. 1 is to anodize the al. which leaves a thin coating of inert material (it is a plating process which achieves a very uniform thickness and an incredible choice of colors). Another is called alodine which is chromic acid which again leaves a thin inert coating on the al. and yet another method is the use of paste like materials to achieve a separation of the materials. Forget the alodine method, probably far too toxic. Anodizing could be worth looking into. This method of protection is used a lot on high quality light weight bike and car parts etc and I'm pretty sure it would be non toxic (however I would do a bit more research first just to be sure). Or some sort of inert paste/wax could do a good job also, but you will have the possibility of contaminating valves and reeds with sticky/gooey stuff. Hope this is of some help. Philos

[A.J.Fedor]

I'd look into the aluminum.    However NOT without anodizing. My brother is a machinist and tells me they have some new anodizing processes that are very good. (and yes, oodles of cool colours) My stock Meisterklasse is at least five years old so I'm guessing it doesn't have the newest anodizing, but it has yet to give me a problem. If I were doing it, (ready to spend the money) I'd go with anodized aluminum. Otherwise an acyclic comb will do ya pretty well.

@ge

[kc_liaw]

what abt. saxony ? i heard its comb is also made from alum. does it has any special technology applied to this cuties ?

cheers

[HallelujahAL]

I just love the acrylic comb on my Seydel Deluxe - which I think is a great compromise in the wood/metal comb debate. I also get to see inside the harp which is fun 
AL

[Thisisme80]

Many thanks all!

I checked with the machine shop guy... he says anodising is a cool option... in the meanwhile, I just realised that Brass costs just a little higher than aluminium... so if I go for Brass then brass plates on brass comb should not react with each other and thereby removes my anodising requirement... also, since Brass is pretty light there will not be too much effort required in warming up the harp as it would be in case of stainless steel (denser the material, more conduction loss... whatever)...

@HallelujahAL: Acrylic is next in my list. I have asked the wholesaler for a sample piece (solid).

@kc_liaw : I agree that I can get the original wood comb. But I have two more chormonicas which are perfect. Now this is my new "experimentonica" ... So, different tone quality eh? Could you please tell me whether it is silkier or rounder? I know I should wait until I get mine but you know human curiosity 

@Ray J : Cost is about the same as buying a new wood comb and shipping it all the way here... Machined metal here is CHEAP!!! If only I were to get this done in mild steel you would roll on the floor laughing at that price...



Regards,
Prash

[kc_liaw]

Many thanks all!

... also, since Brass is pretty light there will not be too much effort required in warming up the harp as it would be in case of stainless steel (denser the material, more conduction loss... whatever)...


@kc_liaw : I agree that I can get the original wood comb. But I have two more chormonicas which are perfect. Now this is my new "experimentonica" ... So, different tone quality eh? Could you please tell me whether it is silkier or rounder? I know I should wait until I get mine but you know human curiosity 


Regards,
Prash

1st of all.. brass is much much heavier than alum. brass also has problem of oxidation. the better solution is plated with silver. example... Suzuki fabulous ..use brass comb plated with silver.  .... i heard JC harmonica in Hong Kong has done customized sample that plated the brass comb with pure gold and the tone color quality is fantastic.

Tone color ?
the stainless steel comb will give a very solid yet quite high pitch tone color, it will be good if u like to have a very "attack" or "crisp and precise" tone color. 

the brass will give you soft, warm and mellow tone color, for me it is too soft until it is  nothing better than wood comb. so i always plated it with silver.  the silver will give the "brighter" tone color and together with bronze.. it give a well balance tone color.... one thing i wish (or yet to ) try is plated with pure gold, but my pocket is not deep enough and there isn't reliable workshop to do ....

cheers

[Thisisme80]

@KC_Liaw: Wow! that is cool, thanks... I am spending about a fifty quid to get the brass comb made... I reckon it is a tad too much but the original metal comb harmonicas are much more expensive... I will check how much would that be to plate it with silver... how many microns would that be?

Is it a good idea to plate the reed plates too?

Regards,
Prash

[kc_liaw]

@KC_Liaw: Wow! that is cool, thanks... I am spending about a fifty quid to get the brass comb made... I reckon it is a tad too much but the original metal comb harmonicas are much more expensive... I will check how much would that be to plate it with silver... how many microns would that be?

Is it a good idea to plate the reed plates too?

Regards,
Prash

how much is fifty "quid" ?.. sorry i m from Asia. not familiar with your local special term.

i do not know how much is the silver plate thickness but i rested my confidence to the workshop who did the silver plating for me.  ..  i would said their tehconogy, machine or workmanship are nop that good.. cuz my silver layer is dissapearing as time goes by... .. guess within short time i have to find another workshop to redo my silver plating on brass comb again..

plating on the reed plate ? good idea but how can you avoid the brass reeds and mylar valves ? or u r prepare to strip all these valves and redo it again after your plating ?   that would be one "hell" new thing we did tough abt it but never give a try due to complexity process..

another better idea u might try is.. just look at super 64x... any possible to add one more plate .. so that it is double plate.. if u can do that .. then the tone color would be.. 'wow..wow..wow'......

[bucketheadshreds]

what abt. saxony ? i heard its comb is also made from alum. does it has any special technology applied to this cuties ?

cheers

saxony comb is plastic- not aluminum i just got one- but I like it - the reeds are stainless steel- thats whats different.

[Winslow Yerxa]

Saxony comb is aluminum according to Seydel's advertising. The one I played, disassembled, photographed, and reviewed for the October 2009 issue of Harmonicasessions.com had an aluminum comb.

If you got a Saxony with a plastic comb, you did not get what the manufacturer described or intended.

The aluminum is covered with gray paint, but if you knock on it, I think you'll find that it's not plastic.

[bucketheadshreds]

Saxony comb is aluminum according to Seydel's advertising. The one I played, disassembled, photographed, and reviewed for the October 2009 issue of Harmonicasessions.com had an aluminum comb.

If you got a Saxony with a plastic comb, you did not get what the manufacturer described or intended.

The aluminum is covered with gray paint, but if you knock on it, I think you'll find that it's not plastic.

AH you are right it is metal- looks like plastic black- dark grey- but it is metal-(I just got one-so new to it) do they paint it?- or is it anodized to prevent oxidation Winslow?

[kc_liaw]

Saxony comb is aluminum according to Seydel's advertising. The one I played, disassembled, photographed, and reviewed for the October 2009 issue of Harmonicasessions.com had an aluminum comb.

If you got a Saxony with a plastic comb, you did not get what the manufacturer described or intended.

The aluminum is covered with gray paint, but if you knock on it, I think you'll find that it's not plastic.

AH you are right it is metal- looks like plastic black- dark grey- but it is metal-(I just got one-so new to it) do they paint it?- or is it anodized to prevent oxidation Winslow?

i would presume it is anodized. .. because paint won't stick on alum long time.   if it is painted, then after sometimes the paint will interact with the salive and desintergrate in small flaks ........ when you play it.. it will slowly draw into your body.. so it is unlikely. 

[Thisisme80]

@KC_Liaw: Wow! that is cool, thanks... I am spending about a fifty quid to get the brass comb made... I reckon it is a tad too much but the original metal comb harmonicas are much more expensive... I will check how much would that be to plate it with silver... how many microns would that be?

Is it a good idea to plate the reed plates too?

Regards,
Prash

how much is fifty "quid" ?.. sorry i m from Asia. not familiar with your local special term.

i do not know how much is the silver plate thickness but i rested my confidence to the workshop who did the silver plating for me.  ..  i would said their tehconogy, machine or workmanship are nop that good.. cuz my silver layer is dissapearing as time goes by... .. guess within short time i have to find another workshop to redo my silver plating on brass comb again..

plating on the reed plate ? good idea but how can you avoid the brass reeds and mylar valves ? or u r prepare to strip all these valves and redo it again after your plating ?   that would be one "hell" new thing we did tough abt it but never give a try due to complexity process..

another better idea u might try is.. just look at super 64x... any possible to add one more plate .. so that it is double plate.. if u can do that .. then the tone color would be.. 'wow..wow..wow'......

@KC_Liaw: Sorry, I spent about 50 Pounds or about 90 US Dollars... Where abouts in Asia, are you from?

[kc_liaw]

@Prash :---  i m from Kuala Lumpur, Malaysia.

[Thisisme80]

Hello all!

I am back with more story.
My machine shop man says that the key way profiles of the chambers in the comb are a bit too complicated to machine. Now, I know they are not, but in all fairness, I am guessing he means that it requires more than one type of cutter.

Therefore, I suggested, why not try a plain and simple key way without any tapers and various holes in it. Just the way they are in a diatonic harmonica. The discussion was diverted to the acoustics of the key ways and the machine shop guy thinks that the shape of the chamber contributes to the tonal color. I did not agree and maintained that the reed produces the sound and the use of chamber is only to contain the air and provide room for the reed to vibrate. Also, my argument is that there were a few tapers given in the chamber to support the thin profile of the chamber walls because they were done on wood and wood could break at that thickness.

My request to any one of you who possess a super 64X or a meisterclasse, is to post a photo of the comb. I want to know the shape of the chambers of those harmonicas and determine whether it is necessary for the chambers to be of complicated nature.

Regards,
Prash

[kc_liaw]

Hello all!

I am back with more story.
My machine shop man says that the key way profiles of the chambers in the comb are a bit too complicated to machine. Now, I know they are not, but in all fairness, I am guessing he means that it requires more than one type of cutter.

Therefore, I suggested, why not try a plain and simple key way without any tapers and various holes in it. Just the way they are in a diatonic harmonica. The discussion was diverted to the acoustics of the key ways and the machine shop guy thinks that the shape of the chamber contributes to the tonal color. I did not agree and maintained that the reed produces the sound and the use of chamber is only to contain the air and provide room for the reed to vibrate. Also, my argument is that there were a few tapers given in the chamber to support the thin profile of the chamber walls because they were done on wood and wood could break at that thickness.

My request to any one of you who possess a super 64X or a meisterclasse, is to post a photo of the comb. I want to know the shape of the chambers of those harmonicas and determine whether it is necessary for the chambers to be of complicated nature.

Regards,
Prash

oh.. i just got a absolute plane chamber stainless steel comb for suzuki scx48.  ... i m yet to try its sound structure & tone color. .. my friend did a prelimary try and said.. the highend note become totally muted.  ... so i guess the taper ramp within its  chamber has its signifincant meaning.  .....  i m considring to do those taper ramp with car body filler .. as suggested by Douglas Tate in his book abt chrome service.

nothing is done yet.. but i m excited with lot of anticipation.

[Vern]

The 270 wooden comb chambers have that shape because they are made on a special-purpose horizontal milling machine.
See http://en.wikipedia.org/wiki/Milling_machine to understand the differences between horizontal and a vertical milling machines.

On the horizontal mill, there can be a separate cutter for each chamber, all rotating on the same spindle. The axis of that spindle is parallel to the long dimension of the comb. All 12 of the chambers on top or bottom can be cut at the same time with a single pass.  This is very efficient. It probably would not work as well with aluminum as it does with wood.  Hohner's mill is probably designed and dedicated to the special purpose of making wooden combs.

Your machinist is contemplating using a general-purpose vertical mill.  The cutter (called an "end mill" ) will rotate on an axis perpendicular to the long dimension of the comb. It cuts the chambers one at a time.

A few years ago I designed a comb that employed a CNC vertical mill to produce over 100 stainless steel combs. It is based on a very old Hohner design, also used for many years by Richard Farrell for machined and molded plastic combs. You may be able to find someone willing to sell one. I still have the CNC part program.  If you would like a copy and an engineering drawing, contact me off-list. With this information, your machinist should have no difficulty making an aluminum comb. i also have some SS blanks left over.  I'll send you two if you will pay for the postage.

The Reynolds number of airflow in the chambers is very low.  This means that the ratio of inertia forces to viscous forces is low.  Thus the shape of the chambers and its effect on the direction of air flow is not critical.  Any design meeting the following criteria will work fine:

Provides clearance for the vibrating reed and the windsaver.
Fits within the outlines of the harp.
Where the chambers have approximately the same volume (cm^3) as the wooden comb.
Provides space for screws where nails go in the wooden comb.

Because Hohner hand-sands the fronts of the assembled combs and reedplates, Every wooden comb and every reedplate can be a little different.  This means that the nail-hole locations with respect to the front edge can be different from reedplate to reedplate. These variations can be avoided if you buy reedplates only and not assembled harps from Hohner.

The aluminum comb Will be more dimensionally stable and heavier than the wooden comb. It will also allow you to tap the screw holes that hold the plates on so you may remove the plates independently.  However, it will not sound perceptibly different from the wooden comb. The aluminum comb will require some kind of coating to prevent corrosion.  That can be anodizing.  Based only on my examination of Seydel's aluminum comb, I believe that their coating is not paint but teflon, probably applied as a powder and heat bonded.

Vern

[Thisisme80]

@ KC_Liaw,
I would be waiting anxiously to learn about the outcomes of your experiment. I reckon, the tone is muted in the last chamber because of air leak and not the chamber profile. I think so because, if chamber profile were to impact I would expect that to happen in the larger chambers rather than the smaller ones. However, from Vern's post, it turns out that neither is correct!

@ Vern,
Firstly, many thanks for replying to my question.

I see what you mean about horizontal milling. Makes the perspective clearer and explains the rounded back wall of the chamber that it is not done on purpose but is an outcome of horizontal milling. Also, you are right about end mill cutter on vertical miller. That is what he is using. Also he has demanded me to get two end mill cutters, one to create the longer grue and the other to cut the taper ramp.

I borrowed the idea of going for a simple chamber from Suzuki Grégoire Maret Signature Series. The comb is a plastic one and has plain and simple cuboidal chambers without any taper ramps. (I have attached a picture of that comb. Courtesy: www.harmonicalessons.com)

I will be honored to receive the engineering drawing and the blanks. I will contact offline.
I am a mechanical engineer by education (and Information technology engineer by profession  ) and therefore would jump at the opportunity of just possessing a design drawing.

I assume SS would also not need any plating and can be used without any damage to my lungs!

Regards,
Prash



Regards,
Prash

[Grizzly]

[a little off topic] So, from this perspective, it appears that the weights do not contact the reedplates!

Tom

[kc_liaw]

yup.. steel definately is ideal material.... .. just that its tone color is soemtime too hard to be accepted by pricky ears.

just has two curious questions,

1. any possible to add an coating on the inner chamber of steel comb ? thus the hard and sharp tone will be tone down to be like bras comb tone color ?


2. just look at the attached pic, where suzuki adds some brass to the plastic comb. to increase the mas and density.  i hava a sc56, what happen if we add brass pieces to sc56 plastic comb .. will it sound better ? now it sound like plastic.


cheers...

[Vern]

Your assumption that steel...or any other comb material or coating..will perceptibly affect the tone is mistaken. The analogy with materials in stringed instruments is seductive but unsupported by either acoustical theory or empirical comparisons.  You may choose your comb material for its stability, weight, corrosion-resistance and cost without concern that it will change the sound of your harp.

Vern

[Suave Blues Man]

Brothers & Sisters of the 270, Thisisme80, HallelujahAL, Grizzly, Ray J, kc_liaw, Philos, A.J.Fedor "Age", bucketheadshreads, Winslow Yerxa, Vern,

     Some time ago when considering a custom 270 from Fathead Musical Instruments, http://www.harmonicarepair.com/ , I came across this site - http://builderofstuff.com/270combs.html .

Be Blues...And Jazz,

Suave Blues Man

[Vern]

The picture of the metal plates in the plastic comb is interesting. 

Since they cannot be effective in altering the sound of the harp, they might be there for another purpose.  They might be there to straighten and stiffen it and to prevent it from warping as it cools or over time. Injection-molded parts having large differences of cross section can distort as the thin parts cool and shrink faster than the thick parts. That is why injection-molded combs are always filligreed with seemingly-useless cavities to avoid thick cross sections.

The function of the metal plates could be structural and not acoustic.  Otherwise, all they would add is cost.

Vern


 

[Grizzly]

The picture of the metal plates in the plastic comb is interesting. 

The function of the metal plates could be structural and not acoustic.  Otherwise, all they would add is cost.

Vern

Not my understanding: I believe Suzuki says that the plates can be removed by the consumer, if he wants a lighter harmonica. No mention has been made about structural integrity.

Tom

[Vern]

The plates may be there to keep the comb straight while it cools and when it is young and tender.  After a while, they may no longer be needed for that purpose.
Another look at the picture suggests that they may be there to surround and re-enforce the screw bosses. 

Do you think they are there just to make the harp feel heftier?

Vern