Thursday, 16 November 2017

The Mysterious Case of the String Pinger

We've been with one of our regulars today, restringing a Korean piano at a church. They didn't mean to become regulars, but they have a rather enthusiastic pianist who somehow manages to keep breaking strings. This is the seventh one we've replaced!

The church manages to get new strings in around two weeks, ordered direct from the Young Chang manufacturer. Perhaps an avenue for us to explore if we don't manage to find a supplier.

We've been working hard on sourcing strings, and enlisted the help of one of our supporters, Fred Cairns, who has been scouring the internet for potential suppliers. We were having no luck at all. No one was responding, until we e-mailed a Chinese company called Steel Wire Cable Wire which we found on LinkedIn. They responded almost immediately, asking how much we need.

Now that is a very good question.

Marion and Désiré spent quite a bit of time down the workshop this afternoon, trying to figure that out.

Here's the original Lirika frame. Working out the strings gets extremely complicated after the bass section. All bass strings have copper wire around them, and they all have an eye at the bottom which hooks around a hitch pin. One hitch pin per wire.

That's straightforward enough.

Bass Strings Attached to Hitch Pins

But when you get to the steel wire for the midsection and treble, it doesn't work that way.

Every note beyond D3# is made up of a chorus of strings. This means that when the hammer hits a note, it hits three strings to sound that single note.

But it isn't as simple as three strings attaching to three hitch pins at the bottom of the frame.

Instead, one note is made up of two lengths of wire, three tuning pins and one-and-a-half hitch pins.

You have three tuning pins along the top. The first length of wire goes from the top tuning pin, down, around the hitch pin, then back up to the second tuning pin. The next length of wire goes from the third tuning pin, down, around the hitch pin, and up to the tuning pin of the next note. So, there are six strings for ever two notes, each note comprising of three strings, sharing half a length of wire between them.

Steel Wire Around Hitch Pins
3 Wires = 1 Note

To make things more complicated, the wire changes both thickness and length as you progress up the piano.

So, when someone asks you 'How much wire do you need?' it's not an easy thing to answer.

We think we have a rough idea of the sizes we need:

Diameter in inches: .043, .041, .039, .035, .033 and .032.

That's 19, 18, 17, 15, 14 and 13 1/2  to American standards.

But we based that on octave samples, so we might be missing a few half-steps. It's been so difficult to find help on this issue, we're going to plough ahead with what we know. We're aiming for a working prototype. We can refine it after that.

Our first step was to figure out where the octaves were, using the hitch pins for guidance. As you can imagine, it's pretty confusing when there aren't any strings remaining on the frame.

We used tuning pins to mark out each set of two notes.

Working on the principle: it's better to have too much than too little, we measured from the lowest hitch pin to the top tuning pin on each set of two notes, timesed that by six (the number of strings in two notes) then added 18", because every string requires an extra 3" to coil around the tuning pin.

Then we rounded up, just for good measure.

The amount of string we think we need for two pianos (our prototype and rebuilding Lirika) is:

19 - 200 ft
18 - 220 ft
17 - 150 ft
15 - 120 ft
14 - 100 ft
13 1/2 - 20 ft

That's what we're guessing at. 

Mapes sell size 19 in a 200 ft coil, but we can't buy from Mapes because of the extremely high postage cost. That's why we're looking to India and China.

We get quite a lot of parts, such as bridle straps and these balance rail punchings, free delivery from China. We're not expecting wire to come with free delivery, but we do hope it's going to be  a bit more affordable.


In other, non-string related news, Désiré has made a start on the keys. We're still planning to cover them in igitenge. Our friend Maia is going to do that for us, but she needs to pick up some resin first.

New Keys Being Made (left)

Original Lirika Action and Keys

1 comment:

  1. This is truly fascinating stuff. Can't wait for the next installment! Good luck with the Chinese supplier.