I’ve worked sprang without a loom, trying different methods.
Well, to begin, here are two frames that I like for the ease of construction and minimal cost.
The first is very like an Archie Brennan frame.
It’s plumbing pipe, elbows, threaded rod and nuts.
At the hardware store, if you ask for half-inch pipe, also ask for half-inch threaded rod.
I’ve been known to attach to my kitchen door. Here I’m working on a pair of socks, two socks created at the same time. I work at a comfortable height, and shove each row upwards and then downwards.