The Revolving Shear Can Opener: A Wheel and a Fixed Cutter That Cut Tin Like Shears

"The outside of the shear E is beveled so as to form an edge which operates against the lower cutter, F, when cutting the metallic plate. This sharp-edged revolving shear E and cutter F obviate the necessity of levers, and also constitute a simple and effectual means for cutting openings in any kind of thin metallic plate." "The handle A is grasped with one hand while the other holds the can, and the point of the cutter E is thrust through the plate of the can, so that the revolving shear E may strike the plate of the can, as shown by the line o o, referred to. Then force the can-opener forward in a manner to suit the form of the opening required in the can."

**Cutter.** Cut 15 cm of 8 mm steel rod. Heat one end and forge it flat, then file it to a pointed cutter F with a straight, square edge along one side. Just behind it, forge or file a small round flat as the plate D and drill it for an M4 screw. **Shear wheel.** Grind a steel washer about 20 mm across to a bevelled edge on one face, as the shear E. Mount it on the plate with an M4 screw and lock nut so its flat face bears against the cutter's side and it turns freely, its edge meeting the cutter's edge as shear blades meet. **Harden.** Heat the cutter's point and the wheel's edge cherry red, quench them, and temper them to a straw colour, as Orne tempered his cast steel. **Handle.** Drive the rod's other end into a drilled hardwood handle with a ferrule of steel tube. **Test.** Hold a can steady on the bench, thrust the point through the lid near its rim, and push the opener forward round the lid. Compare the cut edge with one made by stabbing and levering a knife.

**Eben T. Orne** of Chicago, Cook County, Illinois, received US 53,173, dated 13 March 1866. His shank C was driven into a common wooden handle A with a band B, the cutter F and plate D were forged out of the shaft, and the cutter and shear were cast steel, tempered in the usual manner for cutting metals. His claim is the sharp-edged revolving shear combined with the stationary cutter. **Honest limits.** Forged mild steel rod, hardened only at the surface, and a ground washer stand in for his cast steel. The notebook's shear formula is an approximation; its strength, thicknesses and angles are examples. Your cut can is the result.