The Marine Corps is consolidating its metal worker and machinist specialties into a single new military occupational specialty, effective Oct. 1, 2026, with 3D printing added to the training pipeline alongside traditional welding and machining skills.
Marines currently holding MOS 1316 (Metal Worker) and MOS 2161 (Machinist) will be recategorized as Fabrication Specialists under MOS 1321, according to a message to the force published in late May. The active-duty field will total roughly 390 Marines, combining the Corps’ current 236 metal workers and 157 machinists.

The new specialty is designed to let Marines manufacture parts in remote environments, reducing reliance on traditional supply chains, Marine Corps spokesperson Lt. Col. Melanie Salinas said Friday. Future training will include hybrid systems that combine 3D printing with traditional machining and milling methods. Already, 36 Marines are in the pipeline and are projected to graduate before the October merger takes effect.
Promotion bottlenecks drove part of the decision. Metal workers historically ran into a ceiling at staff sergeant because they competed for advancement against Marines from other engineering specialties. Machinists faced the same problem when vying for gunnery sergeant slots against ground ordnance maintenance Marines. “Fabrication specialists (will) compete exclusively against their peers, ensuring an impartial promotion system and streamlined career options,” Salinas said.
The Marine Corps has used 3D printing to produce replacement parts and, in some cases, entire drones, as has the broader U.S. military. The merger also fits into wider service efforts to retain talent and develop Marines with a broader range of technical skills.
Source: stripes.com










