Hi All, Thanks to the pictures posted by kiwi and fred0325 and the updates to Simon's BSSM, I think I've uncovered enough of the stamp on this saw to ID it as a John Martin & Co. of Sheffield. I can just make out the sideways M next to what I think is the beginning of MARTIN above SHEFFIELD, as well as the base of two Crowns on either side, one between SHEFFIELD and CAST STEEL. However, I need advice on cleaning it up a bit - first things first, the handle is riveted on and I want to know if it's alright with everyone if I removed it by drilling out the rivets. I thought it might be old enough to have been supplied with a riveted handle but the design seems too basic and one of the rivets looks to never have been installed, probably because the handle didn't fit. That said, tips on getting a clearer view of the stamp and cleaning up the plate a bit would be appreciated. I do have an evaporust tank set up and have been experimenting on some early 20th century Disston's with good results (rust removal without too much plate darkening) but this plate has some serious corrosion and I would need to remove the handle to soak the plate. Obviously would also appreciate any info on I (J) MARTIN of Sheffield - I've found a few advertisements for their Cast Steel Files and a few notices of agents in America, but if the dates from BSSM are correct, this would place the saw during the American Civil War. Further, this saw was found in a thrift store here in Northern California, heart of Gold Country, which could potentially explain how it got here. Railroad worker? Someone coming from the northeast to strike it rich? Assuming it came around when it was made and not brought long after by someone moving west. Thanks to all for input.