Military personnel at Symbol A Love Field in Dallas, Texas, use a chart in the machine shop. The chart, issued in August 1918, is labeled "FOR OFFICIAL USE ONLY" and contains steel identifications such as black diamond, blue chip tool steel, cast steel, and cold-rolled iron.

---

Size: 8549px × 5867px
Photo credit: © piemags/NSC / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: activities, american, black, blue, cast, chip, cold, dallas, diamond, field, identification, iron, love, machine, military, photographs, rolled, shop, steel, texas, tool, war, world