In a recent story in JLC, Jefferson Kolle examines the differences between a new handsaw, like you might buy off the shelf at a hardware store, and a vintage saw, like one you might pick up at a yard sale if you're very lucky or buy online from a guy like Matt Cianci, the Saw Wright.
Matt Cianci restores and sharpens vintage handsaws. As he explains, the handmade blade on one of these older handsaws is more likely to be taper ground. Taper grinding means the blades are thicker on the teeth-edge side of the blade, and thinner on the top-edge. “A taper-ground blade won’t bind in the kerf you’ve cut,” Cianci says. “That means the teeth don’t need as much set as those on a modern saw.”
By contrast, the average modern blade has lots of set, and that means the saw cuts a wider kerf. This is necessary so the untapered blade won’t bind. But a wider kerf means the blade is more difficult to control when cutting to an exact line.
Sharpening a handsaw of any type is no joke. Shipwright Louis Sauzedde makes it looks simple enough in his two-part video on sharpening a handsaw.