Leather for Plectra

Following up on the search for “good” leather for plectra (starting on the “Jackrail” about a year ago) I have located a supplier in the US, who has happily supplied me with leather, which Martin Spaink (see below) had recommended, and which is produced by J&FJ Baker & Co Ltd info@jfjbaker.co.uk; Baker is currently short of staff, but they referred me to

Lisa Sorrell: sorrellnotionsandfindings@gmail.com
Sorrell Notions and Findings
217 E. Oklahoma Ave.
Guthrie, OK 73044

with the note, that she deals with their shoe leather sales within the USA, (a shaved bend is typically used in the making of shoes). I include her response to my inquiry below.

I was led to the “Baker” leather by Martin Spaink (see also Fred Sturm’s post 7-31-2015) when I communicated with him in September of last year (just before he died in October). He wrote (on the “Jackrail”, September 18, 2020):

“I confirm here that the Baker tannery has supplied me with excellent traditionally oak-bark tanned leather, cow shaved bend if memory serves. I have made a pluck-o-meter to do some rigorous tests, comparing other types sold for our purpose. Most other leathers were rather short-lived, but the Baker’s I stopped torturing after half a million plucks, and the plectrum said to me: is that all you got, bring it on, I can take it! Since it is a vast investment timewise for me and therefore for the client financially, you really want the stuff to last. One thing: their first question was how many pallets of the stuff I would order? In the end I could convince them to sell me a few square feet if I paid with a credit card.
Sincerely, Martin Spaink. “
Lisa Sorrell sells only shoe-sole sized pieces in pairs, either of 5” or 5 ½ x 13 inches and of 9/10 iron (=0.250” thick) ; I paid $35 for a pair (5 ½ “wide), plus shipping in the US for 8.50.
Various people may have a preference for softer or stiffer “Peu de Buffle”. Though it is not easy to measure “softness” of an inhomogeneous blank, in which the stiffness varies through the thickness, I have measured an overall stiffness of several leathers by measuring the overall bending stiffness (thickness-averaged elasticity modulus, linear elasticity theory) on small cantilever beams cut from strips of leather intended for plectra by determining the maximum deflection under a constant weight (30 grams, 1.25” from support) near the beam’s end; Ialso measured Shore A hardness parallel to the wear surface near the surface (for reference, automobile tire tread is between about 65-75 for highway tires, whether automobile or truck). The following sources have been examined:

1 Hubbard supplied leather
2 Supplied by Harpsichord builder Dave van Ness, El Cerrito, CA. (Italian origin?)
3 J. Rendenbach; Trier, Germany. Producer claims worldwide most durable sole
leather, also oak-tanned;
4 J.&F.J.Baker & Co Ltd, Hamlyns, Devon, UK, the oak-tanned material tested by Martin Spaink and readily supplied in the US by Lisa Sorrell. The data below comes from a sample shipped directly from the UK; a repeat inquiry prompted the referral to Lisa Sorrell. A supplier in Los Angeles (at my door steps) did not wish to bother with me, earlier.

Material Thickness Average Modulus Transverse Hardness
inch PSI Shore A
Hubbard 0.218-0.222 4120 91
David van Ness 0.200-0.204 3270 94
J. Rendenbach 0.206 1360 92
J.&F.J.Baker & Co Ltd 0.236-0,242 2870 96

Not having more “at-hand” experience with these materials except the Hubbard material I cannot give any subjective guidance and personally plan to go with the Baker material, primarily because Martin Spaink had found it useful in his own harpsichord work— a good recommendation— even though it seems to possess the highest hardness. This high hardness is, most likely, responsible for the good wear characteristics he observed, whereas the modulus (a structural bending stiffness property) can be “altered or circumvented” by appropriately shaping the plectrum.