Double-Cutting Shears: Blades That Cut Both Ways

Stitt's object is "to provide a double cutting action for such shears, whereby the knives will cut not only when the handles are drawn together, but will also cut when the handles are drawn apart." Handles a a fit on bars b b, riveted to blades c c. "The blades c c, are sharpened on all edges except the rounded edge h h, at the base of the blades." Drawing the handles together brings cutting edges k k into operation; drawing them apart brings edges l l into operation. A spring e and set screw f "serve to regulate and maintain the bearing of the blades c c as tight as may be necessary." He notes that shears cutting both ways had been proposed, "but such shears have not been made with two double edged blades adapted to pass one another", nor with the blades symmetric to the handles, which matters in grass shears because "the line of cutting must always have a fixed direction relative to the operator".

Mark two equal 5 m lengths of lawn edge with stakes. Trim one with the hedge shears in the ordinary way and time it with the stopwatch. On the second, practise a steady open-and-close rhythm and count strokes per minute. Cut paper strips as a stand-in for a double-edged blade: hold two strips crossed at their middle with a pin and see which edges meet on the closing stroke and which on the opening one. Then sketch Stitt's blade and mark its four cutting edges k and l and the blunt edge h.

**James Thomas Stitt** of Nemegos, Ontario, filed US 1,533,479 on 17 November 1924; it was granted on 14 April 1925. He claims the pair of double-edged blades pivoted between their cutting edges, with handles placed so each moves on its own side of the line of cut. **Honest limits.** Hand strengths, stroke rate and cutting force in the notebook are assumptions; real figures vary widely between people and grasses.