Re: [Harp-L] Re:Was American Chestnut combs, now chromatic combs

["Vern Smith" <jevern@xxxxxxx>]

Unfortunately, there is no easy way to make a Do-It-Yourself 
chromatic comb.

If you glue wooden parts together, you have these 
challenges:
1. You need to have a way of making the parts very 
accurately.  Think of making 22  0.040" thick boards for the 
partitions and then cutting them to the needed dimensions 
accurately?
2. You will need a gluing fixture to hold the parts in place 
while the glue dries.  Arguably, making the fixture will  be 
more work than would be required to make a metal or plastic 
comb.

I have machined combs using handwheels on a tabletop milling 
machine.  It takes me many hours.  My mean-free-error time 
isn't really long enough for the task.  The ultimate in 
frustration is to get a comb 3/4 machined and then make a 
blunder that spoils it.   Aaaargh!!!

Combs have been made by CNC milling.  You must first have 
drawing, then pay about $1000 or more for someone to write 
and debug the part program. In the case of the SS combs, I 
made the drawing and contracted the part programming and 
machining to a local shop.  That's not exactly DIY.  The 
cost is very high for the first comb but gets reasonable as 
the quantities approach 50 or so.  Laser cutting requires 
CNC part programming and an expensive machine but it lacks 
the ability to cut to a certain depth.

I used to work for a company that made drillers and routers 
for printed circuit boards.  It seems possible to use a CNC 
board router to make combs or parts for a comb.  Diatonic 
combs would, of course, be much easier.

One of the local community colleges teaches CNC.  I had 
thought of taking the course, learning to program, and 
possibly using a chromatic comb as a class project.

When making Hands-Free-Chromatics, I needed a material more 
stable than wood.  Until he went out of business, I used 
Richard Farrell's injection-molded ABS combs.  I have often 
wondered what happened to his die.  I asked Richard one day 
on the phone but he couldn't remember. That die is probably 
languishing in dead storage in some injection molding shop 
in the midwest.

After that, I molded my own.  I tried "surfboard 
plastic"...polyester, but found that polyurethane is better. 
Making the mold is a lot of work but, once made, the combs 
don't require a huge amount of work.

A DIY comb is going to be a a lot of ticklish work. 
However, you do have a choice about what you work on.
In any case, it will have to be a labor of love.

Vern

----- Original Message ----- 
From: "David Payne" <dmatthew@xxxxxxxxxxxxxxxxxxxxxx>
To: "Harp L Harp L" <harp-l@xxxxxxxxxx>
Sent: Sunday, June 14, 2009 2:08 PM
Subject: [Harp-L] Re:Was American Chestnut combs, now 
stainless steel(


> There is one way to do it, if you wanna try for fun.
>
>
> A chromatic is essentially two diatonics separated and one 
> switches between them with the slide. With that in mind,
> First, find some sharks with laser beams (Austin Powers 
> reference), then
> Use two pieces of wood that are slightly less than half 
> the thickness of a chromatic comb, as in 1/4 inch sanded 
> down a bit. Remove the laser beams and discard the sharks. 
> Make what is essentially two diatonic-looking combs and 
> sandwich a thin piece of wood between them. Use a good 
> glue and seal the wood like wood has never been sealed 
> before and you have the common man's homemade chromatic 
> comb, common except for the lasers and sharks, of course.
> I've been thinking about this in the back of my mind, 
> using more than one piece of wood and arranging the grains 
> to make a more stable comb.
>
> Dave
> __________________
> Dave Payne Sr.
> Elk River Harmonicas
> www.elkriverharmonicas.com
>
>
>
>
>
>
> * To: "Seth Galitzer" <sethgali@xxxxxxxxx>, "geoff atkins" 
> <geoffatkins@xxxxxxxxxxxxxx>
> * Subject: Re: [Harp-L] Re:Was American Chestnut combs, 
> now stainless steel(Vern Smith, Dave Payne)
> * From: "Vern Smith" <jevern@xxxxxxx>
> * Date: Thu, 11 Jun 2009 10:13:46 -0700
> * Cc: harp-l@xxxxxxxxxx
> * References: 
> <200906102056.n5AKlHfp025607@xxxxxxxxxx><8D2AB00857984667A54CA41BDEC1C7D6@Geoff1> 
> <4A310BE8.2060206@xxxxxxxxx>
> ________________________________
> A few years ago I led a group who cooperated in making 
> over
> a hundred SS Hohner 270 chromatic combs.  We encountered 
> and
> solved some technical challenges.  Now there are over a
> hundred happy harpers tootling away on their SS 270s.  The
> CNC machine had trouble tapping the 1-72 screw holes and 
> we
> eventually did it by drilling out to #2 and tapping by 
> hand.
> It turned out to be more trouble and cost than we had
> anticipated but most participants in the project seem 
> happy
> with the result.
>
> You could not make a chromatic comb with a laser because 
> the
> laser can't penetrate to a controlled depth.  I would be
> interested in knowing how accurately the laser could 
> control
> the edges of the chambers.  Did the laser cut the front,
> back and sides?
>
> There are good reasons for making and using a stainless
> steel comb.  One is just the challenge of overcoming the
> engineering problems.  Others include heft, long life,
> imperviousness to moisture & corrosion, precise & stable
> dimensions, strong steel screw threads and good looks.
> However, it won't sound perceptibly different from the 
> same
> set of reedplates on a comb of any other type of metal,
> plastic, or wood.
>
> I have a still-open, long-standing $1000 wager that no one
> can hear differences in sound arising from differences in
> comb material in otherwise identical harmonicas under
> controlled conditions.  Wanna bet?  ;o)
>
> Vern
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