PEEK (poly ether ether ketone) for jack springs

Many (me among them) have been looking for PEEK wire 0.40 mm (0.016 inch) diameter for use in jacks as substitute for boar bristle or fishing nylon. PEEK is used in gazillion things medical, dental, industrial etc. But it is only sold in big quantities so it has had only limited circulation among harpsichord makers. Its properties hare reported exceptional in reliability and length of life. It takes a bit (only a bit) of set so you can sort-of regulate its strength but it doesn’r weakens with age.
This is reported by primary makers, I haven’t experienced it.

A single maker or a single maintenance-carer would find it uneconomical to buy from the producers (Zyex, Victrex, Monosuisse and others): the minimum they could sell to me was for about 200 big double harpsichord or more.
Now David Gerrard on facebook says he has kilometers of PEEK 0.40 and is willing to sell in bits small enough to be useful for single makers.
The stuff does cost, but then you are not obliged to buy 5,000 meters so it’s a saving. I’ve asked 100 meters wich should be enough for about 15-20 big doubles (that of course I will never make). You can ask as few as 10 meters.

PEEK is not a substitute for brass springs like you find in Italian harpsichords, only for boar springs like the ones in French and Flemish hpschds.

Hope this can be of help to somebody.

Dom

We use fishing line ‘trace’ wire. It’s steel - very springy - covered in thin black nylon or plastic. So, works great, looks nice - the black is good. We get it at the fishing shop for a few dollars a reel. Has been proven over many years for us. And it’s the exact right diameter for jacks. Never had one break or fail, and you can coax the strength with a bit of judicious bending with a small screwdriver etc.

Yes, I think the most important thing is the prevedibility/reliability, more than the length of life (I had to change my nylon springs after exactly 20 years, 1999-2019). Usually I lean towsrds authenticity - egg tempera, wooden jacks, no screws…- but choosing the right boar bristle is an incredible nuisance, many minutes for one jack. If one can simply cut a length from a spool is a great time- and patience-saving.

Marc Vogel sells jack named “Cristofori-type” which have a steel wire as spring. The same jacks I have in my Paris Workshop Delin spinet kit, from 1999 as well, and they are still working fine.

However my preference goes to “Italian” brass springs. Simple to make (just lightly hammer a 0.33 or 0.36 string), simple to mount, simple to change, simple to regulate and set with small pliers or screwdriver. Even the tongue is marginally faster to make, as you don’t need the V-slot for the tongue.

D

I forgot David Gerrard’s email:
EDIT: as per Andrew’s advice, better not to have email addresses in clear do to not encourage spammers. You can find David on Facebook or write privately to me.

D

Regarding Italianate brass leaf springs:

domenico.statuto Domenico Statuto
February 18

[…] However my preference goes to “Italian” brass springs. Simple to make (just lightly hammer a 0.33 or 0.36 string), simple to mount, simple to change, simple to regulate and set with small pliers or screwdriver. Even the tongue is marginally faster to make, as you don’t need the V-slot for the tongue.

I too once tried hammering brass wire to make springs but the result, though functionally satisfactory, was less even than I’d have liked. An alternative, if one has the use of a small rolling mill, is to roll the wire. Or one can buy flat brass shim of an appropriate thickness and cut it into narrow strips; the cutting tends to impart a slight curve, which is helpful and can be evened up by burnishing.

Has anyone here tried quill springs?

Lewis.

Of course - nothing but! Great material, lasts a very long time, unless it gets eaten. Works very well and comes in a range of thicknesses…

Huw Saunders

Ah silly me - I read quill and thought bristle. I haven’t tried quill springs.

Huw Saunders

[posted in the forum website]
I haven’t tried quill springs, don’t even know how are they.

Lewis, you are right about the brass springs hammered from wire being less even than desirable. You could try by putting a iron piece (I use a small piece of iron 1 to 3 mm thick) above the string. Then hammer on the piece of iron, the flat should come out even.

I prefer a hammered string to a leaf because with a leaf you have to devise a mean to block the leaf in position forever. With a hammered string, I simply bore a tiny hole from back (exactly where I want the spring come out from, on the little platform behind the tongue - a platform the Italian jacks have and French jacks haven’t) to front. The exact position here is unimportant. The hole is diagonal of course. I fon’t bore with a normal drill bit but I put a piece of string about 0.40 mm diam. in the chuck. This way no wood is taken away but simply compressed. This helps to both hide the hole and to strictly hold the wire.

I put the round end of the string in the back hole and push till it emerges from the front. Then pull from the front, the flattened part of the string jams in the hole and stays there for centuries. A gentle back-and-forth movement snaps the string on the front perfectly flush with the tiny hole. I then cut the spring at the back with scissors.

Due to the hole being diagonal, it is invisible nor you can sense it if you pass a finger on it. In one of the photos a black dot can be seen, it’s the hole that emerges there. In fact usually the hole is invisible. A micro-drop of water closes it, if needed, because the wood was simply compressed by the drill “bit” (a piece of wire, not a regular bit).

About half of the jacks in my 1699 antique are original, some have still their original brass spring done this way and the still work perfectly.

I attach here some photos. Sorry for the crude working, this were my very first jacks. The spring is uneven because I hammered directly on the wire, and the jack body has all that sort of signs, indents and so on. They worked - and still work - perfectly, though, never had a single repetition issue. It was tha beginner’s luck, because my second rank of jacks, in another harpsichord, were so less good…





And here are pictures of the antique (the darker one) along with a remade jack (not by me).
The exit hole is more visible than I remembered, still it’s unobtrusive.


More on brass and quill jack springs:

domenico.statuto Domenico Statuto
February 19

alvisezuani:

Regarding Italianate brass leaf springs:

I too once tried hammering brass wire to make springs but the result, though functionally satisfactory, was less even than I’d have liked. An alternative, if one has the use of a small rolling mill, is to roll the wire. Or one can buy flat brass shim of an appropriate thickness and cut it into narrow strips; the cutting tends to impart a slight curve, which is helpful and can be evened up by burnishing.

Has anyone here tried quill springs?

Lewis.

[posted in the forum website]
I haven’t tried quill springs, don’t even know how are they.

The only instance of quill springs I’ve encountered is the 1606 clavemusicum omnitinum by Vito Trasuntino (Liceo musicale, Bologna), an instrument whose exceptional design didn’t lend itself to modification or later reuse. I’d be interested to know of others.
The springs are similar in form and position to the more familiar Italian brass leaf springs, but a bit thicker on account of the different material. They are easy to make (like a long plectrum), insert, and adjust.

Lewis, you are right about the brass springs hammered from wire being less even than desirable. You could try by putting a iron piece (I use a small piece of iron 1 to 3 mm thick) above the string. Then hammer on the piece of iron, the flat should come out even.

I prefer a hammered string to a leaf because with a leaf you have to devise a mean to block the leaf in position forever. With a hammered string, I simply bore a tiny hole from back (exactly where I want the spring come out from, on the little platform behind the tongue - a platform the Italian jacks have and French jacks haven’t) to front. The exact position here is unimportant. The hole is diagonal of course. I fon’t bore with a normal drill bit but I put a piece of string about 0.40 mm diam. in the chuck. This way no wood is taken away but simply compressed. This helps to both hide the hole and to strictly hold the wire.

I put the round end of the string in the back hole and push till it emerges from the front. Then pull from the front, the flattened part of the string jams in the hole and stays there for centuries. A gentle back-and-forth movement snaps the string on the front perfectly flush with the tiny hole. I then cut the spring at the back with scissors.

Due to the hole being diagonal, it is invisible nor you can sense it if you pass a finger on it. In one of the photos a black dot can be seen, it’s the hole that emerges there. In fact usually the hole is invisible. A micro-drop of water closes it, if needed, because the wood was simply compressed by the drill “bit” (a piece of wire, not a regular bit).

About half of the jacks in my 1699 antique are original, some have still their original brass spring done this way and the still work perfectly.

Thank you for the detailed description.

For flat springs, for example those of the fifteenth-century clavicytherium at the Royal College of Music, London, one needs an essentially rectangular hole. I’ve used a small punch ground from a jewellers’ screwdriver. The question is whether to crush the endgrain of the jack body, with a flat-ended tool, or to cleave it with a sharp-ended one. I’ve found that a blunt-ended but slightly tapered tool leaves a tapered bottom to the hole, which grips the spring well enough.

Lewis.

I have excellent wooden ZHI jacks in both my instruments. The Flemish has wire and the Italian has peek. I have had no trouble with either. Very occasionally, I have bent the wire ones when fitting plectra, but by taking out the pin and tongue I have been able to straighten them again easily with a small pair of pliers. I dont know why the peek works so well as it looks so flimsy; but it does, so I just accept that reliability with thanks!
David

Just a thought but brass sheet is available in thicknesses from 0.01mm to 0.5mm. Cut it with snips.

For brass shim in the US se, e.g.

https://www.mcmaster.com/sheet-stock/adhesive-back-shim-stock-6/

Carl-Rennoldson Carl
March 18

Just a thought but brass sheet is available in thicknesses from 0.01mm to 0.5mm. Cut it with snips.

eBay

Brass Metal Thin Sheet Foil Plate Thick 0.01 0.02mm to 1mm Brass Strip All Size…

Find many great new & used options and get the best deals for Brass Metal Thin Sheet Foil Plate Thick 0.01 0.02mm to 1mm Brass Strip All Size at the best online prices at eBay! Free delivery for many products!


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In Reply To

alvisezuani Lewis Jones
February 19

More on brass and quill jack springs: [domenico.statuto] domenico.statuto Domenico Statuto February 19 [image]alvisezuani: Regarding Italianate brass leaf springs: I too once tried hammering brass wire to make springs but the result, though functionally satisfactory, was less even t…


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