This is at first glance a very unexciting saw, but I got excited when I first glimpsed the mark on US ebay (had to wait 4 months for it until our daughter arrived for a visit). I think it is a missing link in the development of Spear's business (at first with Mr Love, who didn't last v long). He took young Samuel Jackson as an apprentice during the first decade of the 19th century, and the apprentice quickly became the driving force – his notebooks of selling trips to Europe in the 1820s are in the Sheffield City Library's Archives. At some point I am guessing that Spear, having taken Jackson into partnership, had to order new marks for the saws they were making, and the size of the letters, and the fact (at least I think it's a fact) that the saw was marked with two separate punches, indicate that Jackson is the addition; older saws have simply the Spear mark, which looks very similar to this one. Later still – from only about 1880 I think –the two had new marks made which gave Jackson a more equal place, but they kept on the John Spear name alone for a long time, maybe as an extra product line? Now…as to dating. Here is a tentative dating sequence for Spear (& Jackson) marks up to about 1920: it may not be wholly consistent with the dates I put in the saw book, and I apologise if I'm being annoyingly inconsistent; I can't show the saws as well here, but the datings are based on the whole appearance as far as possible. I can't seem to place a caption, but the dates of the sequence below – all on backsaws except where noted – are c1810, c1815, c1820, c1830 (* the one I'm getting excited about), c1840, c1840, c1850, 1850-1870 (handsaw mark), 1880-1920
Thanks for the timeline with the marks, Simon. That is the sort of thing that is so helpful with dating. The American sourced S and J was lovely when you bought it, and it still is so.