Labor of Love or Just Crazy?

Hello Harp Techs, a couple of decades ago, I ordered from Brendan Powers a CX10 Richter tuned harmonica. This is not a spelling error. Brendan surgically removed two holes from the stock HOHNER CX12 harmonica! The KOCH reed plates he installed onto the shortened body would enable me to play--with the button out--an A harmonica and with the push of a button (slider), I would magically be playing a half step higher (1 semitone) on a Bb harmonica. It was more of a novelty for me, and therefore; the CX10 sat on my shelf for all those years. Until now…

In general, Chromatic harmonicas are uncomfortable for me to hold, especially 16 hole models, the twelve hole CX12 hole is tolerable, but rarely do I need the upper octave. I didn't care much for the playability of the now discontinued Hohner 260. If only Hohner made a ten hole version of their popular CX12!

That wanting was the genesis of my crazy project. This is how I built my solo tuned CX10 chromatic harmonica:

Top is the 12 hole Hohner 270 and bottom is the 10 hole Hohner 260 chromatic harmonica

Top is a stock CX12. Bottom is the modified Brendan Powers CX10 body that I will repurpose with modified plates from a CX12

Look carefully and you will notice that Brendan Power surgically removed the section that contained holes 1 and 2. The remaining end piece was “welded” (ABS cement) back to the main body

Not that dissimilar to how I built my MAG7 (Magnificent 7) seven hole Special 20 harmonica (years ahead of the KongSheng Baby Fat harmonica ;o). I removed a section of three holes and ABS welded the right end back onto the main comb

Plastic cleats were welded in place on the inside of the body for strength 

Top is the CX12 stock comb and bottom is the “sawed off” CX10 comb that Brendan Power modified for me

Using the existing stanchions, I mark the locations of the clearance notches on my donor CX12 reed plate

Cut notch with Dremel cutting wheel

Square file makes nice work of shaping the notch

Here I used Blue Painters tape to temporarily secure the reed plate. Finishing Brads worked well (aligned by the molded index ports) to center punch the reed plate for preparation of drilling and tapping 0-80 new holes for the reed plate screws.

Drill the 1/16” pilot holes for the 0-80 tap

Thread the pilot holes into the bottom reed plate with 0-80 tap

Seat CX12 reed plate onto CX10 comb and scribe the cut line

Dremel rotary tool with cutting wheel worked well for trimming off the excess reed plate

In this view you can see I had already removed the four higher octave reeds

After cutting and filing, check the fit of the modified reed plates. Eventually the slider button will be inserted in this cavity.

Here is a view of the lower octave end

I removed the windsavers to provide me easy access to the reeds for profiling and reed plate slot sizing

After reed profiling and tuning, my next step was to install forty new Makowski windsavers. This was also a good time to cover up the unused holes and reed slots. I used 3m Micropore Medical Tape to mitigate air leakage. Once completed, I assembled the reed plates onto the comb using the original Hohner CX12 machine screws. Before inserting this assembly into the body, I indulged myself with one final process

From the players' listening proximity (not audience), I found the CX12 to be a tad muted sounding. Above you’ll notice that my solution was to create “near field monitors” on my HOHNER Jazz CX12. I drilled three 3/16” strategically placed holes. I wanted to repeat this proven strategy for my CX10 as well.

“Measure twice, drill once”!

Perfect

With a countersink bit, finger-turn into the holes to remove unsightly burrs. OK, ready to insert reed plates and slider into place 

The ten hole CX10 looks terrific and plays to perfection!

Your Harpsmith, Kinya