alex_holden

If you have a local accordion tuner, they should be at home with the sort of reeds that are in a Norman concertina. It's possible to experiment with reed weighting by putting a little blob of Blu-tack on the tip. If you're happy with the result you could then make the change more permanent with solder.

Sounds great, well done Jake and Cohen!

You would need to remake the reed pans because duets have lower reeds (= larger chambers) on the left and higher on the right, whereas Englishes are fairly evenly distributed. You would also need some extra reeds for the overlap region. The number of buttons shown on the diagram implies a fairly large instrument, bigger than an English Treble.

I just tried abcm2ps on MacOS (installed via Macports) and it correctly processes Q: values higher than 127, which suggests an issue with the DOS version included with EasyABC for Windows. Just for kicks, I tried giving it a tempo of 32768, and as expected it printed -32768 in the output (showing that it's storing the number in a signed 16 bit short variable).

Looking at this header file, tempo is defined as a short, which is usually 16 bits, not 8. Perhaps the compiler that was used for the DOS version of abcm2ps is treating short as 8 bits? Or maybe it's an older version that is using char instead of short? The parser function is reading the value into an int, then blindly copying it into a short (not good practice). I would be inclined to just change the type in the header file to an int.

You're on the right track. Whatever program EasyABC is using to render the ABC (abc2ps?) is storing the Q value in an unsigned 8 bit variable, without correctly validating that the number will fit in a variable of that size.

That's very interesting, thanks.

Which sort of skiving machine is that Mike? I only have a Scharf-fix.

When I said skiving with a knife, that's what I meant really. I made two sets of bellows with that method but have given up on it because the carriage with the knife blade in it wobbled about too much, causing an inconsistent edge on the card strip.

I believe Krazy Glue is a brand of cyanoacrylate/superglue. I have used superglue for this job several times and not had one come back yet. Note that not all superglue is created equal, and the really cheap tubes are IMHO a false economy. I'm currently using "Everbuild Industrial Grade Superglue GP" (medium viscosity). If you keep it in the fridge while not in use it lasts longer.

Works for me using UnZip, 7z, and Archive Utility on a Mac. The download link gave me a zip file that contained a Readme.txt and a second zip file called "Alan Day's Concertina Tutorial.zip". The inner zip file has the following MD5 checksum: 57e56b3e8304848a9adfc164a177c1c2 (use a checksum utility on your copy of the file - if the number doesn't match, you have a corrupted copy). I notice your screenshot seems to be saying the archive is only 223KB - it should be about 100MB.

I have an electronics background and spent some time thinking about electronic concertinas before going down the traditional reed route instead. The biggest thing that puts me off developing any kind of low-volume electronics product is the cost of EMC compliance testing. It can easily add thousands to the R&D budget, especially if you want to sell it internationally. Obviously not an issue if you're a hobbyist building a one-off for your own use.

If anyone has found a UK source of dense 0.8mm card that is stiff enough for bellows and not prone to delaminating I'd like to hear about it. I'm currently using 1mm millboard from Hewit. Vintage bellows that I have dismantled did seem to use a slightly thinner, denser card (possibly laminated from two or more layers of thin card?). I make mine from individual cards and chamfer the top edge of each one using a belt sander (I've tried skiving with a knife in the past but got less consistent results). I no longer assemble them on a collapsible mould because I like to be able to move them as I glue the parts on, to reduce the amount of tension built into the hinges.

Good luck Geoff, hope you will be on the mend soon!

I used acetal buttons on my first instrument and I flame polished them. Expect to melt a few before you get the hang of it. There's a video here: