The 32-button Lachenal (made c. 1860) I recently posted had no thumb straps, so I've started making replacements.  I've sourced most of the materials, the only problem being the screws holding the straps to the ends: each strap needs two 1/4" #1 gauge screws and one 1" #1 gauge screw. I bought the small screws from the Vintage Screw Company, but they could not supply the long screws.   I sent e-mails to Concertina Spares and to Steve Dickinson, but got no answers. A search of the inter