This is the gear and ratchet tensioning device.
The warp threads go through the dowel and are tied around an old knitting needle. The dowel slides out of the holder to make the threading easier. When I weave it gets secured with a string that acts as a washer to stop it from pulling out. This is the tensioning device that secures the warp supply. I drilled two holes in a scrap block of oak and sliced it into three. The wing nuts loosen so the warp can be released and combed. They get tightened again for weaving. There are pieces of leather on the blocks.