This is the eleventh entry in a nineteen part series that covers the construction of one of my saws from start to finish. For links to the other entries, please see the full chronological index. -Ed.
Cutting the blank
***When working with spring steel, it pays to be careful. The edges can be very sharp, and wearing eye protection and gloves when handling it is highly recommended.***
My blades are made from polished and blue tempered 1095 spring steel, hardened to Rc 48-51. It is available from any number of suppliers, and is sold in various thicknesses and sheet sizes. I buy it in rolls that range from 10 to 25 feet in length.
After uncoiling the steel, I place tape where I will cut, then mark the lines on that with a pen. All of the cuts are made with a Beverly shear, first cutting to length and then to width.
The shears leave a decent edge, but they do need to be cleaned up with a file. The ends are checked for perpendicularity to the edge that will be the toothline; the backside is checked for straightness. This second step is extremely critical – the edge of the blade that will be installed into the back must be either dead straight or slightly convex. When the back is driven onto the blade, any concavity will result in a bow along the toothline. The edge should also be chamfered or rounded over to make installation in the back easier. Do not, however, form a knife edge, as this can damage the back as it is driven on.
Whenever I hold the blade in a vise, I protect it from scratches with a layer of tape or paper.
Finally, the back end of the blade must be clipped to fit in the handle. I seat the blade fully into the back, then slide it into the handle as far as it will go, making sure to keep the back parallel to the top of the mortise. After taking the measurements, they are transferred to the saw blade itself, which is then cut and deburred with a file.
Next up: shaping the back, a most exciting endeavor.