| Number | Name | Date | Kind |
|---|---|---|---|
| 99961 | Star | Feb 1870 | |
| 396479 | Green | Jan 1889 | |
| 1129699 | Ludwig | Feb 1915 | |
| 1626540 | Kimura | Apr 1927 | |
| 2402000 | Young | Jun 1946 | |
| 3512261 | Viollet | May 1970 |
| Number | Date | Country |
|---|---|---|
| 0197534 | May 1923 | GBX |
| Entry |
|---|
| Popular Science, "Dual-indicating caliper has metric scales", Nov. 1970, p. 103. |
| "Planar Gauge", Trend-Lines Catalog No. 502C, Chelsea, Mass. p. 18 (no date). |