3D printed tongue block trainer
Posting in case anyone is interested in 3D printing harmonica parts.
Bit of history: I have a Hohner 270 and its pearwood comb broke twice (too much drool I guess :-P). The first time it was under warranty so I sent it for replacement. The second time I decided I was done with wood combs and instead got a 3D-printed replacement comb from Brendan Power (the "PowerComb", which I got in purple, really cool, you can see it on my profile picture). I have since wanted to experiment with 3D printing harmonica parts. This is my first attempt at it. I have access to some 3D printers at work for free, so I thought I'd give it a try and print something useful.
So I searched for anything harmonica at Thingiverse and found this model for a tongue block trainer https://www.thingiverse.com/thing:1579178, and I have printed two copies.
The photo shows the two 3D-printed (with PLA filament) harmonica tongue block trainers. The red one was printed upside down as recommended by the author so the front surface is flat and smooth. The white one's front surface has burrs that I later removed with a bit of sandpaper.
I'm also printing right now a 270 comb from Thingiverse, https://www.thingiverse.com/thing:3166485 and, if things go well and I get some time to learn the needed software, my plan is to adapt this model to fit 10-hole Hohner 260 reedplates, as I also own a 260 I'm very fond of (my first Chromatic).
I'm working using reedplates from Hohner's Koch 980 slide harp for a retuning project - same basic frame as a Hohner 260. I'm interested to see if you come up with a 3D printed 260 comb.
I also have a friend who plays 260-based chromatics and was asking me about replacement combs a few months ago. So please keep me posted about your progress with developing a 10-hole chromatic comb.
After a couple of attempts, and with the suggestions of Winslow and a friend who also has a 3D printer, I managed to design and build a PLA comb which pretty much works.
I bought a used 260 on eBay for $36 which was in excellent condition, and used it as a guinea pig for my refurbishing experiment.
I also bought 1.6M x 16mm screws and M1.6 hex nuts to hold together the reed block, and to fasten the mouthpiece to the comb. The design has a sinkhole on each side to hold the nuts in place, so machine screws can be used to hold the mouthpiece. This has an important advantage over using the original wood screws: since the screws attach to the nuts instead of biting into the comb, fastening and unfastening the mouthpiece screws (for cleaning etc.) will not slowly destroy the screw holes. Some which actually doesn't happen slowly to PLA plastic (the plastic will break but doing that a couple of times). This section view shows how the right sinkhole for the captive hex nut meets the mouthpiece screw hole orthogonally:
This is the comb while trying the mouthpiece screws on it:
This is the comb side to side with the one the harp came with. It shows I didn't properly measure the spring post hole, which almost became a showstopper since the spring didn't attach properly to the slide. But thankfully I was still able to make it work by sanding the comb, a step you nevertheless need to perform to fit the comb for air tightness:
The (almost) finished harp. It's not very airtight because I still need to do some more sanding and widen a couple of the nail holes in the reed plates so I can fasten screws to hold the reed block together. But it plays good enough to be usable, at least for me:
I just need to fix the spring post holes placement and I will make this available to others.
So cool!