The Wedge Boot Tree: A Screw That Stretches Foot and Leg Together

"The piece B is several sizes shorter than the foot or sole of the complete last, and is inserted first into the foot of the boot to be stretched. The instep-piece C is inserted, as shown in Fig. 2, and afterward the wedge-piece A is inserted into the V-shaped opening." "At the same time the top of the leg is also stretched by means of the cap E and collar R, said cap being provided with hooks h to seize and hold the top of the leg".

**Sole and instep.** From hardwood block, saw and rasp a sole piece like the back two-thirds of the boot's inner sole, 2 cm thick, and an instep piece like the front of the foot whose back face slopes, so that laid in the boot they leave a V-shaped gap. **Wedge.** Saw a wedge to fill that gap with its faces at 20° to its centre line, checked with the protractor, and drill a 10 mm hole 2 cm deep in its top. **Screw and cap.** Cut a plywood disc wider than the boot's opening, drill its centre 10.5 mm, and fix an M10 nut over the hole with a second nut. Screw 30 cm of M10 threaded rod through. Lock a 12 cm hardwood dowel on its top between two nuts as a T-handle. Turn four screw eyes into the disc's edge and open them into hooks. **Test.** Mark the instep piece's position on the sole piece, turn the screw 5 turns and measure how far it moved with the caliper. With 1.5 mm pitch at 20° it should be about 5 × 1.5 × tan 20° = 2.7 mm. Then spray the inside of a leather boot lightly with water, measure the ball width with the caliper, fit the tree, hook the cap on the top of the leg, tighten firmly and leave it a day. Measure again.

**Edward E. Thresher** of Reed City, Osceola County, Michigan, assignor of one-third to William McNamara, filed US 245,240 on 12 February 1881; it is dated 2 August 1881. He described the whole felt-boot process: wool carded into batting, felted over a pattern with steam, fulled down smaller than the finished boot, stretched, steamed and stretched again, and finally set on his tree. **Honest limits.** Hardwood pieces, an M10 rod and screw eyes stand in for his tree, and the leg pieces with their nuts on inclined bearings are not built. A damp leather boot stands in for a felt one. The notebook ignores friction; its force and angles are examples. Your caliper readings are the result.