We received many correct entries when we asked readers to identify March’s Mystery Tool, a stair saw used in building staircases.
Of the entries, this month’s winner was sent in by Alan Fitzhugh of Gananoque, Ont. He wrote about fond memories of seeing this tool in his grandfather’s workshop. “I remember this tool from my grandfather’s basement workshop in Verdun, Que., back in the early ’50s,” says Fitzhugh. “I thought it was a ‘kid’s saw’ because of its size, but he told me it was really a stair saw.”
The stair saw is actually an adjustable-depth handsaw of eight inches to 15 inches in length, used to define the sides and depth of a cross-grain rabbet or mortice. The tool became known as a stair saw because it was used extensively in stair building when cutting out the mortices or rabbets for the stair treads and risers in the stair stringer.
The saw has a built-in handle and the saw blade is set in the centre of the bottom, which is adjustable in depth so that the cheeks on the bottom of the saw act as depth stops to regulate the depth of the mortice. After the stringer is marked with the tread and riser locations, a saw cut would be made on each side of the mortice to the set depth. Then the waste material between the cuts would be chiselled out to the depth of the saw cut.
Some of our readers wrote that they had used this type of saw themselves or watched carpenters use it to build staircases in the ’40s, ’50s and ’60s. Fitzhugh says that his grandfather made his own stair saw for building staircases.
These days a router can do the job more quickly and easily, so the stair saw is now likely to be found in museums, antique shops or hanging on the wall of an old workshop.