alex_holden

It looks like the Canadian customs tariff schedule is different; the USA schedule doesn't list that code. This is the (slightly confusing) description I found for 9205.90.10.90 in the 2023 Canadian schedule: Wind musical instruments (for example, keyboard pipe organs, accordions, clarinets, trumpets, bagpipes), other than fairground organs and mechanical street organs. - Other - Accordions and similar instruments; Bassoons, clarinets, English horns, fifes, flutes, oboes, piccolos, practice chanters, recorders and saxophones; Keyboard pipe organs; Mouth organs - Other: - Other

It looks like code 9706 "Antiques of an age exceeding 100 years" is duty free (however the item might need to be accompanied with documentation proving its age).

Technically 9205.90.15 is "Accordions and similar instruments: piano accordions". It's probably more correct to use 9205.90.18 "Accordions and similar instruments: other", which has a duty rate of 2.6%. The customs inspector might be ignorant of the difference, on the other hand they might not.

Yes there is. The most commonly available pitch is metric coarse. Metric fine is unusual particularly at small diameters. The non-standard threads that Wheatstone and Lachenal etc. used are extra-coarse. As far as I'm aware there is no standard thread that is similar to them, regardless of metric or imperial. I use 8BA because it's about the same diameter as the vintage ones (2.2mm) but has a finer pitch of 59TPI vs about 44TPI. I believe most other modern makers use either M2.5x0.45 or (less common) M2.2x0.45, both of which have a pitch of about 56.5TPI.

The problem with using a custom extra-coarse thread like the vintage makers did is you would also need a matching tap for threading the nut plates in the bellows. Making such a thing is not easy, and although you can have custom taps made they are horribly expensive and they don't last forever. Ideally you would also want to have a matching die made for threading the bolts. While it is possible to single-point thread the bolts (if you have a screw cutting lathe, which I don't), it is much more finicky, time consuming, and error prone than using a die. If you went through all that, you would then have the same situation as we now have with vintage instruments: future owners and repairers would curse you for having made an instrument with non-standard threads that they can't easily buy taps and dies for. The other reason for using a modern pitch thread is it leads to a larger diameter core for a given major diameter, so the bolt is stronger and less likely to shear in use. As the maker, I probably have to put the ends on and off more times while building the instrument than the owner ever will, and I don't find the extra turns to be a major issue.

Imagine if they had cast it in bronze!

It kind of looks like they took an impression from a wooden upper action box, so the metal is a lot thicker than it really needed to be.

Exactly, you shift everything to make A4 work out to 440.

The tuning app I use (Tonal Energy) has a setting to automatically adjust the pitch so that A4 still ends up at 440Hz (or whatever frequency you give it) even if the root note of the scale isn't A.

I’ve pondered doing that occasionally, but I haven’t come up with a great way to cut the slot in the small size needed (please don’t suggest milling it with a 0.6mm dia end mill). A possibility might be sawing the slot in the normal way and then gluing/soldering a short length of thin wall tube to the outside, then profiling and polishing the head afterwards. It would likely end up a slightly larger overall diameter though.

It sounds like you're making the new springs considerably stiffer than the old ones were. That's fine if it's what you prefer, but many players value a 'light action', i.e. buttons that don't take a lot of force to press. It is important for all the buttons on a particular instrument to be fairly consistent.

Is it one of these? https://www.concertineitalia.it/en/chromatic-concertinas/chromatic-concertina-mod-a18-concertine-italia/ If so it's a miniature English. The problem with miniature concertinas is they have quite a limited range and don't have all the accidental notes, so you need to carefully pick/transpose tunes to fit it. There are some previous topics on the forum discussing this model, e.g.

Like the spring and pin mechanism Dana Johnson invented?

Adding an extra turn to the coil will make the spring less stiff. Shortening the top arm will make it stiffer. Perhaps there were locations where they needed the top arm to be shorter because there wasn't room for a standard spring, so they added an extra turn to make up for it.

Thanks! The bottom end plate is nickel plated nickel silver and the top one is aluminium. Interesting idea. I've not tried it myself, but Google says yes it can. The chemicals are a bit pricey though.