About 3003|Essentially pure aluminum with a bit of manganese. Designed for forming and drawing, not machining. In the shop, this stuff is soft, gummy, and smears on your tools. Machinists describe it as slightly better than
1100 but still miserable. It’s the standard for deep drawing operations, beverage cans, and heat exchangers. If a customer specs 3003 for a machined part, it’s usually because they need it for a subsequent brazing process. Hardened condition (H14, H18) machines a bit better than annealed, but don’t expect clean cuts. Sharp tools, flood coolant, light cuts, and patience.