The Tensioned Razor Strop: A Screw in the Handle Pulls the Belt Tight

"My invention relates to that class of razor-strops having stropping-belts, the tension of which is regulated by adjustable tightening-plates; my object being to cheapen the manufacture of such plates, and at the same time produce plates of such construction that the rigid wooden bodies of the strops will be less weakened by the holes entered by the projecting pins or lugs of the plates than by the forms of tightening-plates heretofore in use." "From this construction it follows that the holes in the end of the wooden body of the strop, entered by the said lugs and screw, will all be in different planes relative to the grain of the wood, and said body will, therefore, be less weakened by said holes than where the holes for the pins or lugs of the plate and the hole for the adjusting-screw are all in the same horizontal or vertical plane across the end of the strop". He adds that the plate may be used with strops "the rigid bodies of which are made concave under the belt".

Hang the strop from a hook, or clamp one end, and pull the free end taut. Hook the force meter to the free end to see how hard you are pulling. Look at the razor's edge under a loupe against a light: a dull edge shows as a bright line, and a sharp one shows almost nothing. Slice a sheet of paper held by one corner and note how cleanly it cuts. Strop 20 laps on the taut strop, as in the program, then check under the loupe and on the paper again. Now let the strop hang slack, strop 20 more laps, and check again. Write down the strokes, the pull on the force meter and what you saw each time.

**Joseph R. Torrey** of Worcester, Massachusetts, filed US 295,840 on 27 December 1883; it is dated 25 March 1884. His claims cover the tightening plate with struck-out lugs, not the tensioned belt itself, which he describes as already in use. **Honest limits.** The sag formula treats the belt as an unbacked string pressed at one point; a belt lying on a flat rigid body barely sags at all. Force, torque, pitch, efficiency and hole sizes are examples. What you see under the loupe is the measurement.