CNC Machining & Assembly of a Trigger Frame for the Military Industry

From design and machining to final assembly and packaging, Schmid Tool and Engineering recently completed the production of a trigger frame assembly for a firearms manufacturer. Complex in nature, this project involved fabricating and assembling 28 unique parts into multiple sub-assemblies that came together to form the final piece. All operations required adherence to strict military specifications and stringent tolerances of ±.0004".

Multiple machining techniques were used to produce the parts, ranging from CNC milling and Swiss turning to broaching and stamping. Although fabricated primarily from aluminum and steel, the trigger frame assembly also had plastic components that were injection molded. Conducted in our 5S Lean facility, the multipart assembly operations involved using our 20 ton hydraulic press and a custom designed, multi-axis staking die to deliver 6,000 units of this 5" x 7" assembled part.

Secondary operations involved heat treating, plating, applying a manganese phosphate coating, which protects the surface from corrosion and increases its resistance to wear, and finally applying a black anodized finish. All completed trigger frame assemblies were packed in partitioned boxes and shipped to the customer.

To learn more about this project, or to learn about our other services, please contact Schmid Tool & Engineering.

Trigger Frame Assembly for a Small Arms Military Application
Trigger Frame Assembly for a Small Arms Military Application

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Trigger Frame Assembly Project Details

Product Description
This trigger frame assembly is used within in a small arms military application.
Capabilities Applied/Processes
  • Investment Casting Mold
  • Machining Fixtures
  • Gaging
CNC Milling
Swiss Turning
  • One Assembly Comprised of 3 Sub-Assemblies
  • Comprised of 28 unique Parts
  • 5S Lean Assembly Area
  • Utilized 20 Ton Hydraulic Press w/ Custom Multi-Axis Staking Die
Manganese Phosphate Coating
Heat Treatment
  • Partitioned Box
Overall Part Dimensions
Length: 5.000"
Width: 7.000"
Tightest Tolerances
Material Used
4130 Steel
7075 Aluminum
Various Other Materials
Material Finish
Black Anodize
Industry for Use
Fire Arms
6,000 EAU
Standards Met
Multiple MIL-Specs

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