I see quite a few "counterbores." I'll explain why I put that in quotes:
Counterbores and spot facers are basically the same thing. The difference is their use. Counterbores are used to make a recessed area in a surface that is large enough to accommodate the head of a fastener (and sometimes, the tool to engage that head), while spot facers are used merely to make a spot square to the hole for the fastener to grip the surface with full contact, or something engaging or running on that surface to have a square surface of contact.
Counterbores generally have a radius ground in the corners to make a hole without a sharp corner. This is to avoid points of stress concentration that can lead to cracking.
Spot facers are often used on bosses that extend above a flat surface, and don't need the radius if the boss is smaller than the outside diameter of the tool.
I see that many of the "counterbores" have sharp corners, and would call them "spot facers."
That said, I would guess that these may be clock making tools. A second guess would be for making gauges or other instrumentation.
