Delrin nut, stock made from oak and maple mill cuts from Home Depot, a polypropylene rope for a bow string, and a bunch of scrap parts and hardware I had laying around cobbled together into surprisingly comfortable shooter. Loose laminate prod from fence tension bars (thanks @kenh).
The new prod (old one broke) is working like a charm. was able to check the draw today with a bathroom scale and it weighs in at 65 to 70 pounds at 13" powerstroke.
Performance is currently a disappointment, clocked a 500 grain bolt at 102 fps, or 12 ft.lbs, on the chrony . I suspect my 1 inch brace was just a tad too low to be practical, so I shortened the string for a 2 inch brace. Sun went down before I can clock it again though.
Excuse the rubber band, it's acting as a temporary return spring for the trigger mech. Would replace later with a proper coil spring.
Nut and side plate removed here. Just a simple sliding pin to lock and release the nut, actuated by a lever (which I bent into a sort of grease gun trigger to accommodate a pistol grip).
If you're wondering, the clip spring was bent from an aluminum gutter hanger. Have a lot of those laying around from my old job as a roofer.