I picked up these two threaders at a sale the other day, most of the tools were from the 40's and 50's. The larger one is a LL-3123, and seems to be 5/16nc thread, a 5/16 nut does thread on. The smaller one is LL-2503, and I thought it looked like 1/4nc, but a 1/4 nut is a tiny bit too small to...