I knew what these where once, a long time ago, but I've since forgotten. Tapered pins. I have lots of them. What are they for, what are they worth? And, who wants them?
They are for aligning field assembled machinery. In the field it is almost impossible to ream a straight press fit hole. For these pins the hole is finished with a matching taper reamer and the pin is driven in until it seats solid. It is much easier to control the taper reamer to make a uniform taper for accurate alignment.