In my quest for the perfect jeweler’s saw blade for sawing out f-holes, I once landed the world’s last supply of these antique blades, defunct blades from a closed hardware store, bought at a now-closed tool store in downtown Chicago. The brand is Gilbert, and I tracked them down to around 1890 or so. They’re perfect for the job, sawing a wide kerf with lots of turning room, quickly, but not making a mess.
Notice that they appear to be made by a machine-driven chisel upsetting the edge of a strip of steel that’s then hardened after the teeth are cut. From the contour on the top of the teeth, I decided they probably started out as wire which was rolled flat. The photo is quite magnified: the height of the blade, from the bottom to the tops of the teeth is a little less than 1.5mm, and there are around 20 teeth per inch.
I have wire! I have chisels! Just for fun, after seeing a video on making rasps (a similar process to the way these blades were made), I decided I’d try making a blade the way they might have done it 300 years ago, by hand. I took a piece of soft iron wire, 1mm thick, and pounded it flat, for a start, then I started chopping.
OK, so I’m not ready for prime time. I can see the similarity to the original, but it’s harder than it looks. Before I could finish a whole blade, I cut all the way through, accidentally. I posted this photo on a forum where a member of the rasp company was posting: he noted in response that it takes several years to train someone to cut a rasp to their standards, and I believe him.
Here’s the video that inspired me, if you feel like trying your hand at rasp-making.