Custom metal pipe fittings are the connectors that decide whether a fluid or gas system holds pressure, resists corrosion, and assembles without leaks on the first try. From a simple threaded elbow to a cast manifold branch, the fit between mating faces and the integrity of the thread or weld prep determine the whole line’s reliability. This guide covers the fitting types we make, the materials that suit each service, how they are produced, and how to specify them so the parts arrive ready for the weld rather than for a rework bench.
What Counts as a Pipe Fitting
A pipe fitting is any component that changes direction, splits flow, adapts size, or provides a serviceable joint. The common families are elbows and bends, tees and crosses, reducers, caps, unions, couplings, and flanges. Each carries the same nominal bore but behaves differently under pressure and thermal cycling. We machine threaded fittings on CNC turning centers where the seal depends on thread form and seat flatness, and we form bent fittings where the geometry is a continuous tube rather than a threaded joint. The choice between them is mostly about whether you need to disassemble the joint later or weld it permanently into the line.
Materials: Stainless, Carbon, Brass, Alloy
Material selection drives both cost and service life. 304 and 316 stainless cover most corrosive and hygienic services; 316L is preferred where weldability and chloride resistance matter. Carbon steel is the value choice for non-corrosive utility lines. Brass fittings suit low-pressure water and gas where machinability and a clean look matter, while specialty alloys step in for heat or chemical extremes. We consult on grade during quoting so the fitting is not over-specified (wasted cost) or under-specified (premature failure). The same material advice behind our custom metal brackets work applies: match the alloy to the environment, not to the catalog default.
How Fittings Are Made
Production route follows the geometry and volume. Threaded elbows and unions are turned from bar on CNC lathes; large or complex bodies are sand cast or investment cast for near-net shape, then machined at the sealing faces. Where two halves must be joined, we use TIG welding with controlled heat to avoid distorting the bore. Bent fittings start as tube and are formed on CNC bending equipment that holds the centerline radius and wall thickness. Picking the right combination is what keeps a fitting accurate and affordable at the volume you actually buy.
Threaded vs Flanged Connections
Threaded fittings are fast to assemble and easy to service, which is why they dominate smaller bore lines. Their weak point is the thread root, which concentrates stress and can leak if overtightened. Flanged connections spread the load across a bolt circle and seal with a gasket, which is why they are standard on larger pipe and high-pressure services. We produce both, and our custom metal flanges are faced and drilled to match standard bore patterns so they drop onto existing flanges without field modification. The decision is usually made by line size, pressure, and how often the joint must be opened.
Pressure, Code, and Corrosion
Every fitting has a pressure-temperature rating tied to its material and wall schedule. We work to the standard you name and provide material certificates where the system requires traceability. Corrosion is the silent failure mode: a fitting that looks fine on the outside can be thinning from the process side. We match the alloy and any surface treatment to the medium, and for outdoor or coastal service we coordinate galvanizing or coating so the finish reaches the threads and seats without blocking them. The same discipline we apply to precision turned parts carries into fittings where a tenth of a millimeter at the seat is the difference between seal and seep.
Quality and Inspection
Fittings are inspected where it matters: thread form and go/no-go gauging, seat flatness, bore concentricity, and surface condition. For pressure parts we can add dye-penetrant or hydrostatic checks on request. Because a bad fitting can take a whole line offline, we treat the sealing features as the critical characteristics and document them. Batch consistency matters more than a single perfect sample, since the thousandth fitting has to seat exactly like the first or the installer loses time chasing leaks that were made weeks earlier.
How to Request a Quote
Send the drawing or sample with material grade, pressure class, end type (thread, flange, or weld), quantity, and any code requirement. Tell us whether the line is corrosive, hygienic, or high-pressure, because that changes both material and inspection. With those inputs we return a price and lead time and flag any long-lead alloy up front. If you only have a sketch, our engineering team will help Close the spec so the quote reflects a real, manufacturable part rather than an assumption that breaks at assembly.
From Prototype to Production Run
Most fitting programs start with a sample to prove fit on a mock-up, then scale once the thread and seat are locked. We keep the sample fixturing for the production run so the thousandth part matches the first, and we record the turning and weld parameters so a reorder two years later lands identical. If volumes climb high enough that machining dominates cost, we will tell you—sometimes a cast or forged route is cheaper, and we would rather save you the hours than bill them while the line waits for fittings that cost more than the system should allow.
Frequently Asked Questions
Which material is best for corrosive service?
316 or 316L stainless for most chloride and chemical exposures; we move to specialty alloys only when temperature or media demand it.
Can you make both threaded and flanged fittings?
Yes. We produce threaded fittings by CNC turning and flanged fittings machined to standard bore patterns, often in the same program.
Do you provide material certifications?
We supply material certs and traceability where the system requires it; name the code at quote time so we scope inspection correctly.
What pressure ratings can you hold?
We work to the standard you specify and gauge every threaded and flanged feature so the rating is real, not nominal.
How fast can you deliver samples?
Sample fittings typically run in days once the drawing and material are confirmed; we flag long-lead alloys before you commit.
Ready to Start Your Project?
Get a build-ready quote on your custom metal parts within 24 hours. Share your drawing and our engineers will respond with process, lead time, and pricing.
