Leather, Felt, Cloth, or something else?

Materials
1

Leather, Felt, Cloth, or something else?

What material should be used on the lower rear surfaces of upper manual keys where the coupler dogs contact the key? Disclaimer: I am an oboist by education, computer engineer by trade, and a period furniture maker by avocation. My keyboard expertise is limited to finding the A for tuning.

That said, I am making replacement keyboards for my 1973 Hubbard French double, similar, I think, to Claudio’s instrument. I have Grant O’Brien’s drawings of the 1769 Taskin instrument at St. Cecilia’s Hall, as well as a photo of the keybed removed from the instrument, and both clearly show felt as the material in question.

Doing some research it appears that there are nearly as many opinions as there are builders and restorers.

I’m curious to learn whether there is a consensus of opinion on the best material, or whether the choice remains in the realm of historical precedent and personal preference.

2

The ZHI system of putting felt cloth on the end of the upper key levers, where the jacks sit, and folding it round the end of the lever to the underneath, where it quietens the contact of the coupler dogs, has stood me in good stead for over 25 years. (The cloth is held by small nails, and not glued.) Other than ZHI in Stonington, CT, I do not know where to acquire such material; but others here may well be able to help.

David

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3

My Hubbard French double kit (1988) uses the same ‘wraparound’ felt system (with tacks not glue) and has worked well. The instructions describe the material as “red bushing cloth.”

4

I have always used leather and tacks

David Law

5

I’ve used wool cloth, the type used for making winter coats. As there are so many, best is to go personally and choose the right combination of thickness and weaving. Stores have often remains of cloth, too short to be used for a coat but more than enough for two or three harpsichords.
Or, if you are located in Europe, Marc Vogel sells cloth for harpsichords. Not as good as a well-chosen wool cloth in a store, but good enough.

Other sources are Zuckermann in USA and The Paris Workshop in Paris or any of their agents (listed on their website).

Dom

6

I have #625 of Frank Hubbard’s kits (purchased 1973). On page 72 of the Instructions under
"IX - Assembling the Action, Keyboards, Registers, Guides, and Nut Pins” there is listed

"3 rolls red bushing cloth for backs of upper-manual keys”

But I do not know whether bushing cloth is always manufactured the same way, though Hendrik Broekman (last owner of the Hubbard store) assured me that the harpsichord “industry” is very conservative in what it uses.

| JAKurowski James
February 9 |

  • | - |

Leather, Felt, Cloth, or something else?

What material should be used on the lower rear surfaces of upper manual keys where the coupler dogs contact the key? Disclaimer: I am an oboist by education, computer engineer by trade, and a period furniture maker by avocation. My keyboard expertise is limited to finding the A for tuning.

That said, I am making replacement keyboards for my 1973 Hubbard French double, similar, I think, to Claudio’s instrument. I have Grant O’Brien’s drawings of the 1769 Taskin instrument at St. Cecilia’s Hall, as well as a photo of the keybed removed from the instrument, and both clearly show felt as the material in question.

Doing some research it appears that there are nearly as many opinions as there are builders and restorers.

I’m curious to learn whether there is a consensus of opinion on the best material, or whether the choice remains in the realm of historical precedent and personal preference.

Visit Topic or reply to this email to respond.

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Wolfgang G. Knauss
Theodore von Karman Professor of
Aeronautics and Applied Mechanics, emeritus
California Institute of Technology
Pasadena CA 91001

626 395 4524 Phone — Office
626 798 3793 Phone — Home
626 797 0405 Fax — Home

7

James, it occurred to me that you might want the wording of Frank Hubbard regarding the fixation of the bushing cloth. He instructs on page 81 under item (15):

The backs of the upper keys are to be covered with red bushing cloth as shown in the elevation. (I am too lazy right now to dig out the big sheet with the elevation drawing on it). Rule a line lightly across the backs of the levers 5/8” from the rear.

Begin by tacking the end of a strip of cloth to the underside of the key opposite this line. Use two tacks near the corners*. Pull the cloth taut around the end of the key and tack through the line a the top of the key lever. Set a combination square so that the ruler protrudes 3/4” from the head and use it as a gage to cut off the cloth in an even line beyond the tack heads.

  • My experience has been that sometimes too big a tack will split the wood if the tack is too close to the edge. Later, I think, Hendrik Broekman suggested using staples of an appropriate length, instead.

Good luck.

| wgk Wolfgang Knauss
February 9 |

  • | - |

I have #625 of Frank Hubbard’s kits (purchased 1973). On page 72 of the Instructions under
"IX - Assembling the Action, Keyboards, Registers, Guides, and Nut Pins” there is listed

"3 rolls red bushing cloth for backs of upper-manual keys”

But I do not know whether bushing cloth is always manufactured the same way, though Hendrik Broekman (last owner of the Hubbard store) assured me that the harpsichord “industry” is very conservative in what it uses.

| JAKurowski James
February 9 |

  • | - |

Leather, Felt, Cloth, or something else?

What material should be used on the lower rear surfaces of upper manual keys where the coupler dogs contact the key? Disclaimer: I am an oboist by education, computer engineer by trade, and a period furniture maker by avocation. My keyboard expertise is limited to finding the A for tuning.

That said, I am making replacement keyboards for my 1973 Hubbard French double, similar, I think, to Claudio’s instrument. I have Grant O’Brien’s drawings of the 1769 Taskin instrument at St. Cecilia’s Hall, as well as a photo of the keybed removed from the instrument, and both clearly show felt as the material in question.

Doing some research it appears that there are nearly as many opinions as there are builders and restorers.

I’m curious to learn whether there is a consensus of opinion on the best material, or whether the choice remains in the realm of historical precedent and personal preference.

Visit Topic or reply to this email to respond.

You are receiving this because you enabled mailing list mode.

To unsubscribe from these emails, click here.

Wolfgang G. Knauss
Theodore von Karman Professor of
Aeronautics and Applied Mechanics, emeritus
California Institute of Technology
Pasadena CA 91001

626 395 4524 Phone — Office
626 798 3793 Phone — Home
626 797 0405 Fax — Home

Visit Topic or reply to this email to respond.

In Reply To

| JAKurowski James
February 9 |

  • | - |

Leather, Felt, Cloth, or something else? What material should be used on the lower rear surfaces of upper manual keys where the coupler dogs contact the key? Disclaimer: I am an oboist by education, computer engineer by trade, and a period furniture maker by avocation. My keyboard expertise is limi…

Visit Topic or reply to this email to respond.

You are receiving this because you enabled mailing list mode.

To unsubscribe from these emails, click here.

Wolfgang G. Knauss
Theodore von Karman Professor of
Aeronautics and Applied Mechanics, emeritus
California Institute of Technology
Pasadena CA 91001

626 395 4524 Phone — Office
626 798 3793 Phone — Home
626 797 0405 Fax — Home

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8

Just curious… I am currently rebuilding a very poorly (and only partly) assembled Hubbard French double kit.
I only got part of the documentation with it.
Where can you locate the kit serial number (other than in the documentation)?
Claude Pellerin
Australia.

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9

I am not sure where I found mine, any more; I think it was on the invoice.

| Claude Claude Pellerin
February 10 |

  • | - |

Just curious… I am currently rebuilding a very poorly (and only partly) assembled Hubbard French double kit.
I only got part of the documentation with it.
Where can you locate the kit serial number (other than in the documentation)?
Claude Pellerin
Australia.

Visit Topic or reply to this email to respond.

You are receiving this because you enabled mailing list mode.

To unsubscribe from these emails, click here.

Wolfgang G. Knauss
Theodore von Karman Professor of
Aeronautics and Applied Mechanics, emeritus
California Institute of Technology
Pasadena CA 91001

626 395 4524 Phone — Office
626 798 3793 Phone — Home
626 797 0405 Fax — Home

10

Yes, the serial number was on the invoice (or bill of sale or whatever it was called). Mine came packed in several cardboard boxes, and the serial number was written on each of them.

Also, if you have the large mylar drawing that was supplied with the kit, make a note of which revision you are dealing with. Mine was the 1985 version by Hendrik Broeckman.

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11

Decades ago I was told that felt & bushing cloth are not the same - for what it’s worth. Maybe somebody with more experience & knowledge can comment in greater & more accurate detail.

I found this factoid @ http://www.heckscher.co.uk/bushing-cloth/ :

““Little known fact about bushing cloth: the “white centre”, a long time distinguishing feature of fine bushing cloth is in fact a throw back to the early days of the manufacture of this cloth when the dye (cochineal) was too primitive to permeate through the entire thickness. The result was a white centre. For many years the cloth manufacturers have restricted the application of modern dye in order to maintain a good white centre!””

Regards,

Dale

12

Anything that damps sound is good. Most people use felt. Felt can be made from anything, but I have a gut feeling wool felt has the most sound absorbing properties. This is in agreement with Domenico’s use of wool coat fabric.

This sort of felt from Vogel is fine:

Marc Vogel GmbH - Felt stripes for string damping (vogel-scheer.de)

I’d like to emphasize that the almost universal method of wrapping around and fixing with tacks is because the air layer thereby produced also helps with damping extraneous sound from the action. Never glue the felt on.

Although I suppose they had staples in the 17C, personally I think tiny tacks are much nicer. Use two on each side.

Leather can have the advantage that it is more durable, and moths don’t eat it.

13

My Hubbard kit (as all the instruments with the modern-type Kluge keyboards) had a heavy coupling. The coupler dogs in the lower manual pushed against screwed-in coupler buttons in the upper manuals. These were wooden cylinders about 7mm diameter, to which cylinders of 3mm-thick felt was attached. It was obvious that part of the action weight was due to the deformation of that felt when one played the lower key. I consulted this in detail with dear late Martin Spaink back in 2014. He provided a substitute for the thick felt: a set of 2mm-thick wooden cylinders and a piece of 1mm-thick leather, from which I produced the bushings. The improvement was not impressive but clearly noticeable.

14

Piano supply houses offer many kinds and thicknesses of bushing cloth, in pre-cut strips and in sheets.
The better quality of bushing cloths are somewhat hard surfaced, compared to the lesser quality, which are fuzzy. The problem with all cloth, felt or leather cushions is that over time, with pressure, they flatten and become harder. The fuzzy cloths can be very erratic with humidity change.
Ecsaine is a kind of synthetic buckskin, originally made for military boots, if I remember correctly. It is almost identical to buckskin by sight and touch, but is of consistent thickness, texture and strength. It has virtually equal nap in all directions. The piano industry is adopting ecsaine in the action points that traditionally used buckskin. The Wessell, Nickell & Gross action company states that after over a million impacts they can discern no change or wear in ecsaine covered parts. Although buckskin or ecsaine may be slightly less damping than cloth or felt when new, perhaps over the long term ecsaine may be unchanging.
I’ve been exploring the use of ecsaine in various experiments. Ecsaine can be stiffened with lacquers (such as B-72 paraloid) and laminated to make hard or soft leather-like plectra. It can make very strong leather-like hinges. It’s not quite soft enough to make jack dampers, though I have not tried the very thinnest in a mouse ear configuration.
Four thicknesses of ecsaine and many, many thicknesses and types of wool cloth and felt can be purchased from Pianoteksupply.com
Wool cloth and B-72 can be purchased from Pianofortesupply.com, and ask them about ecsaine.
[I repeat some of this information now and then because these materials have made piano work a lot easier, and they are potentially as useful as delrin in harpsichords.]

15

There appears to be a problem here for ordinary mortals:

This website is intended for piano technicians ONLY and orders cannot be fulfilled for the general public.

16

Dear James et al

There are several common methods of covering the upper manual keyends. The neatest is a single layer of scarlet bushing cloth stretched around the end, with two small nails (not blued cut tacks) both ends. Some makers use an additional layer, perhaps only on the underside. Garlick uses much thicker box cloth. Hyman famously used thin pigskin on top of the bushing cloth—very elegant. In some old French harpsichords, the cloth extended much further on the lower side of the key, offering a padded fall onto the otherwise bare backrail of the upper keyboard.

All these cloths are subject to progressive wear by the repeated contact with the top of the coupler dogs, often only noticeable to the owner when midrange notes through the coupler begin to clack, a sign that the cloth has worn clear through to the bare wood!

Here’s the video of how I fit and neatly trim the upper keyboard cloth:

Andrew, yes, a number of the piano supply houses (Schaff, Jahn…) don’t want the nuisance of dealing with public enquiries, so they are strictly trade accounts only.

Regards

Carey

17

Yes, it’s just that Ed recommended it.

18

Is Marc (don’t know his last name) of the Instrument Workshop (fortepiano.com) still around? The site seems to be up and running, and it used to serve private users. I bought Voss wire and damper felt from the store a few years ago.

Roberto

19

A few years ago I bought a couple of pieces of “woven felted wool cloth” from a retail outlet catering for drapery, sewing, and tailoring supplies. There was a good choice range of thickness and stiffness.

Probably best handled before buying, but the pieces I got are smooth, and not inclined to unravel. Feel much less harsh than the felt used in pianos.

I regret that my plans to use them have been stalled by illness and family troubles, but I had in mind dampers (the stiffer material), jackrail padding (softer material), and other general felting.

No idea if that particular shop is still in business, but I expect there are many more like it.

Frank.

20

I think we should clarify the difference between ‘felt’ and ‘cloth’.
Cloth is woven on a loom from threads produced by a spinning process.
Felt, properly speaking, is not woven at all but consists of
roughened-up fibres pressed together in a random fashion. Felt is
broadly speaking weaker than cloth and much less resistant to rubbing,
so it is unsuitable for the rear ends of upper-manual keylevers which
are constantly being rubbed by the coupler dogs. Bushing cloth is a
fairly close-woven cloth, specifically designed for rubbing situations
(e.g. the balance mortices of piano keys) and would be much more suitable.

By ‘woven felted wool cloth’ I imagine the vendor meant that the surface
layers of the material had been loosened and then compressed, to produce
a softer layer over a tougher, woven base layer. That’s my guess, anyway.

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