Not all threaded parts are available off the shelf. When a fitting requires a non-standard thread, size, or head, it must be machined to exact specifications. A customer approached us for a custom brass plug: a threaded fitting with a large external thread on one end and a square drive head on the other, designed to seal or close off a port. Since no catalog part matched their requirements, we CNC machined the plug from solid brass to the customer’s precise dimensions.

The external thread provides both sealing and holding functionality, while the square drive head on the opposite end ensures a secure grip for a wrench, allowing the plug to be tightened to the correct torque. As a sealing fitting, the thread must be clean and accurately formed to ensure a leak-free seal when seated. Brass is the ideal material for this application—it machines smoothly to create precise threads, resists corrosion in fluid handling and outdoor environments, and its natural malleability aids in thread sealing. These properties make brass plugs and fittings a standard choice in plumbing, hydraulics, and instrumentation systems.

Part type: Custom Brass Plug (square head, threaded sealing plug)

Material: Brass

Machining Process: CNC Turning

Surface Finish: As-machined

For sealing fittings, thread quality is critical. The external thread had to exactly match the customer’s non-standard pitch and diameter, and maintain concentricity with the plug body to ensure proper seating in the mating port without leaks or cross-threading. We cut and gauged the thread to the specified fit, maintained concentricity by machining the thread and body in a single setup, and sized the square head to ensure it works with a wrench without rounding. Delivering accurate non-standard threads is where custom CNC machining clearly outperforms off-the-shelf parts.

We provide custom CNC machining services for low-volume production and rapid prototyping for design verification.  Click Here to Upload Your CAD Files