Over a year has passed, but I finally have a somewhat useable lathe. "Pole" is in quotes because, like many people these days, I don't actually use a pole for the spring action. Rather than using a bungee cord, my substitute is a fairly stiff spring. The spring is attached to the short arm of a lever, while the string that wraps around the workpiece is tied to the long arm. This gives me a lot more travel with a stiff spring. The concept comes from a design by M. Hulot from 1775. He devised a similar lever mechanism so a pole lathe could use a short stiff pole and so be used indoors with limited space. Hulot's design is discussed in one of Underhill's books.
The lathe is built mostly out of standard 2x4's. The treadle is simply a 4 foot 1x10 attached by a hinge to a plywood board, I trimmed the end to lighten it somewhat. The poppets are ordinary maple boards from the Borg, laminated to build up the necessary thickness, with big hex head screws for the pikes. The the poppets are held in place on the bed by trimmed dowels serving as wedges. Using dowels let me simply drill a 1" hole with my brace, and not worry about fitting wedge with a rectangular cross section. I used the same technique for the more permanent problem of locking the bed to the uprights.
