I just picked up this J Taylor & Son back saw because of the unusual domed nuts. The saw itself looks like it had been nailed to the side of a barn. It is beyond saving, in my opinion. I bought it since I'd not seen this style of saw nut before. It isn't really a split nut and not a normal domed nut, as the slots are cut into the sloped side. Does anyone know when this saw might have been made? The spine is marked with "J Taylor & Son, Sheffield" and with the lamb trademark.