| System | Period | Rows | What it dates |
|---|---|---|---|
| Case — the tang stamp and related firms (c. 1900 → the twentieth century) | c. 1900 → the twentieth century | 5 | There is no direct “Case stamp → year” table in the sources checked. What exists are firms' years of operation and dated connections: Crandall Cutlery |
| Grind, spine, scales, etching — era markers of a straight razor | 1700s → mid-1900s | 16 | Shared layer for all straight razors: it does not date precisely, but it cuts off an era. All rows are printed wordings from a shop-page guide review |