alex_holden

My starting pressures on the tuning bellows are similar to Chris's, maybe slightly lower. My tuning pressure is lower, around 0.5". I also try a much harder yank on the bellows after each adjustment to check that it doesn't choke. The bellows are the same size as used on a typical 6 1/4" concertina. I haven't measured the maximum bellows pressure in an assembled instrument, but 3" or 4" sounds plausible based on how much force it takes to make my pressure gauge max out at 2".

Personally I ran into difficulties with accurately installing cylindrical nut inserts in bellows frames, so I went back to the traditional flat 2mm brass plates held on with two small wood screws. I make my own end bolts with an 8BA thread, which is the same diameter as the vintage ones but a bit finer pitch. They work fine and are possibly slightly stronger. At one point I looked into the possibility of having a custom tap and die made to match the vintage Wheatstone thread pattern, but it was going to cost hundreds of pounds for a one off.

The outer cloth hinge goes all the way around (the ends butting up in the middle of a side). That holds the sides together while you put the gussets on, then the leather binding will strengthen it further.

80% sounds high to me; if you over-humidify there's a risk of encouraging mould and rust. Note that temperature variation can cause a problem too, if you keep it in a room that is intermittently heated/cooled. Room heats up, relative humidity falls, humidifier gives out moisture into the air; room cools down, relative humidity rises, excess moisture condenses out of the air onto the instrument and the case lining.

I use about 20mm wide strips for the peak and valley hinges. The strips that connect the bellows frames to the end cards are the depth of the frame + about 10mm. I use a thin but very strong linen cloth sold in the UK under the "Fraynot" brand; presumably you can find something similar locally. I cut the strips on the bias (i.e. at 45º to the warp). I attach them using rabbit skin glue brushed onto the cards, trying not to get any on the hinge part of the cloth. On one set of bellows I tried something that looked similar to your second link. It had a rubbery glue already applied to the tape. It was a pain to use because it stuck instantly to the card and couldn't be repositioned, and the resulting hinges were quite bulky and stiff compared to what I normally use.

You need to inscribe more runes on it. https://en.wikipedia.org/wiki/Harald_Bluetooth

Try Wallace Calvert, his email address is on this page: https://glasgowcan.org/wallace-calvert

Oops, Graham's right, this is in the baritone range. Therefore it would probably need to be bigger than 6 1/4" to fit in the larger bass reeds, and I would expect the cost to go up because it takes it further away from a standard instrument.

It would certainly need some redesign but I can't really comment on how much time that might take. Any new layout is a significant amount of work. He would have to modify the end plate and action boards as well as the reed pans.

No comment on the playability of the system, but I believe it is buildable, at least using traditional construction (either parallel or radial) in a standard 6 1/4" wide instrument. It is a little unusual to have more buttons on the left hand than the right. If you send this to a maker I suggest you specify the octave number on every note to avoid potential confusion (middle C = C4 is pretty standard; it is called "scientific pitch notation").

I used a Schärffix 2000 (bought before the Chinese started knocking it off) for all my bellows until the most recent set. The Schärffix does work OK and some leatherworkers seem to love them, but I always found the disposable razor blades very frustrating. A good blade (I'm using the Personna ones) cuts almost effortlessly when it's fresh out of the packet. Then it starts going dull within a few inches of skiving, and as it gets duller the force needed to pull the leather through the machine increases. As the force increases, the edge of the blade and the top arm of the machine start to deflect, altering the depth of cut. You also end up stretching the leather sometimes. I found I was constantly having to measure parts and tweak the depth setting. Often something would go wrong and the blade would dig in and ruin the piece I was skiving (I got better at avoiding that with practice). Every few feet you need to stop and change the blade, which will cut to a different depth than the old dull one, so you have to do some test cuts and adjustments before you can get back to skiving real parts. After skiving all the parts for a set of bellows I would have a small pile of worn out blades to dispose of. I recently upgraded to an old industrial Fortuna bell skiver machine. It is more complicated to set up than a Schärffix and has its own quirks and issues to deal with, but for me the rotating bell knife with its built in sharpening system is a massive improvement over disposable razor blades. I wouldn't claim to be 'masterful' yet, but I did manage to produce an acceptable set of parts with it:

Hi Brian, you can buy reed wax from accordion/melodeon parts suppliers, e.g. http://www.cgmmusical.co.uk/CGM_Musical_Services/Reed_Wax_Nails.html#1

I think David’s right, my previous numbers were a bit on the high side. I’m assembling a new set of bellows right now and I made the gussets for it 0.5mm thick.

Something that hasn't been mentioned is that you also need a thin metal shim to slide under the tongue while filing it. I made mine from an old feeler gauge. Don't try to push it all the way to the clamp. After each filing session before putting the reed back into the instrument it's a good idea to blow the metal dust off with compressed air. Occasionally filing throws up burrs on the edges of the tongue that can interfere with the fit; they can easily be scraped off (I use a scraper tool made from a needle file with all the teeth ground off).

Pretty much, yes. That should be a reasonable starting point anyway. Bellows are a complicated subject and I haven't made two sets exactly the same way, but it wouldn't be too helpful if I gave the true answer, "thick enough but not too thick".