Making the Frame

Stock

Plane two birch arms and a pine stretcher square and true. The Norwegian Forest Museum saw has a stretcher of knot-free pine 87.3 cm long and 3.9 by 2.6 cm in section, and birch arms 45 cm long ¹; scale them to your blade. North House’s tool list (hand plane, 1-inch and 1/2-inch chisels, mallet, mortise gauge, sloyd knife, fine saw) is all this needs ².

Mortise and stretcher

The stretcher’s ends sit in mortises at about the middle of each arm ¹, or just above the midline ³.

1. Mark the mortise centered on each arm’s width, at mid-length or a little above.
2. Gauge it about a third of the arm’s thickness wide and chop it through from both faces.
3. Cut a tenon on each end of the stretcher to fit, not glued and a little loose, so the arms can rock on it. On one museum saw the tenons are wedged inside the mortise ¹; at home, a snug fit that still pivots is the goal.

Shape the arms

Old Norwegian arms are rectangular in section, thickest at the mortise, and rounded toward the blade end to make grips; the tops are notched or grooved to hold the cord ¹. Shape them with saw, knife, and plane:

• Taper each arm from full width at the mortise toward both ends.
• Round the lower third into a comfortable grip.
• Chamfer all edges.
• Cut a shallow notch across the top end for the cord.

Handles and blade

The blade hangs at the bottom of the arms in two handles that pass through round holes in the arms, slotted to take the blade, which is fixed with a pin or rivet; some museum handles are octagonal so the blade angle can be set and held ¹. North House’s optional ⅝- and ¾-inch bits and turning chisel point to turned handles ².

1. Bore a hole through the bottom of each arm.
2. Turn (or knife-carve) a handle with a shank that fits the hole, a shoulder, and a knob.
3. Saw a slot in the shank end for the blade.
4. Cross-drill for a pin that passes through the slot and the blade’s end hole. Blackburn’s blades have 3/16-inch holes and it sells blade holders and pins ⁴.

Toggle and cord

Make the toggle from a hardwood slat about 22 to 26 cm long, the size of the museum examples ¹. Wind the cord in several loops around the notches at the tops of the arms (Tools for Working Wood uses about four loops of braided line ³), tie it off, slip the toggle between the strands at the middle, and twist. As the cord twists, the arm tops draw together and the blade tightens. Rest the toggle’s end against the stretcher to keep it from unwinding ¹.

True it up

Tension until the blade pings when plucked. Sight down the blade: it must lie in the same plane as the frame, not twisted, or it will wander in the cut. Adjust by turning the handles slightly. Make test cuts along and across the grain.

Try it

Make the toggle-and-cord mechanism first with two scrap sticks and a dowel before you shape the arms. Feeling the leverage as the cord twists shows how much tension the arms and mortises must carry.