alex_holden

I wouldn't attempt to glue that core back together. When you make a new one, you can measure all the dimensions you need from one of the not-broken buttons. I turn my button cores from acetal because it's fairly cheap, easy to machine, and will probably last forever. If you would prefer to use wood for originality, the ideal is something very dense and fine grained like boxwood, but I suspect the originals were just beech. I've used both beech and box for buttons, and box is much nicer. A dense fruitwood like apple or plum would probably work fine too. If you want I can post you a bit of acetal or box.

I see; I guess that should work. Let us know how it turns out.

I wouldn't worry about 8000 RPM with a small diameter solid carbide bit - they can probably cope with tens of thousands. There's a potential issue with it overheating and burning the wood if you don't use a high enough feed rate for the spindle speed (because it's rubbing rather than cutting), but it may not matter if the cutter is sharp enough. Presumably the collet is rated appropriately for the router it's meant to go in. The only problem with gluing the wall in after you cut the slot is that the slot can't undercut the wall, which means the chamber has to be wider than it would be otherwise, so you can't fit as many chambers into the pan, and higher pitched reeds respond better if the chamber volume is as small as possible. I made my own custom shaped dovetail cutter from silver steel (drill rod), which has its pros and cons. It took three attempts before I made one I was really happy with. The reason it's so long is so it can reach down into a deep bass chamber after the walls are in place. I'm convinced Wheatstone must have used a cutter with a similar shape, having examined some of their reed pans.

Thanks Alison, that was lovely.

The easiest way to tell is if the levers and springs are a different colour. Brass is yellow and phosphor bronze has a more coppery pinkish hue. Even if they are brass they probably still have decades of life left in them.

They seem to have used custom taps and dies that were coarser than modern threads. The major diameter is almost the same as 8BA, and indeed that is what I use on my new instruments, but 8BA is significantly finer pitch than the old bolts. If you have a screw cutting lathe with the right gear ratio, it should be possible albeit time-consuming to turn new bolts that match the old thread. Making a working tap that small is theoretically possible but outside my ability (I attempted it a couple of years ago). I also looked into having a custom tap professionally made and the cost was eye-watering. I believe Adrian Brown managed to make a tap that cuts the Jeffries thread.

These are my most commonly used pliers for spring work: https://tronex-tools.com/collections/pliers-chain-nose/products/chain-nose-pliers-short-tip-1 You can find cheaper ones with a similar nose shape from beadwork or jewellers suppliers. New springs will always need to be adjusted to give your preferred button force. Whether to replace them all depends on what condition they are in. If they are rusty steel or modified safety pins, I would replace them as a matter of course. If they keep breaking on you, then perhaps it's time to change the rest of them. Likewise if you're a pro player and don't want to take the risk of an antique spring going pop in the middle of a gig.

If, as @David Barnert says, this was only done on the early square Bastaris, my guess would be that they originally built the prototype with an Eb on that button. After it was finished somebody found they really missed having a low F#, but it wasn't practical to add a button in the correct position without completely redesigning the internals of the instrument so they simply swapped/retuned the Eb reeds instead.

Also solid aluminium buttons. I seem to recall Geoff Crabb told me 9155 was made for a member of a marching band. I believe aluminium became more affordable after the first world war and was fairly commonplace by the 1930s.

I think it should look like this.

If you use a sharp lathe tool (I grind mine from HSS and hone the edges), it isn't difficult to turn to finished diameter in a single pass. That goes for acetal, aluminium, and free turning brass. Something like stainless steel might need multiple passes. I'm actually using a self-made acetal soft collet in this picture to avoid scratching the button, which isn't ideal because it is less rigid and less grippy than a steel collet. It's hard to see in this picture, but the tool has a slight radius at the tip to leave a strengthening fillet at the junction between the two diameters.

It's 3mm or so veg tan cowhide leather. I punch out little discs then drill a hole through the middle.

Acetal is slightly easier to machine. Both will work fine as buttons; it's mostly a matter of personal taste. Personally I dislike the appearance of plastic buttons, particularly on a vintage instrument.

I've made an instrument with solid aluminium 6060-T6 buttons and they turned out very nicely. I have the sort of sweat that tarnishes brass very quickly, but I didn't notice any reaction with the aluminium buttons.

Looks like this one? https://www.ebay.co.uk/itm/384446015777?hash=item5982c4a921:g:rv8AAOSwfQdhHhRa Buyer beware: the seller has zero feedback.