Pipe Fittings
7679 Products
LILY Bearing stocks 7,679 pipe and pipe fitting SKUs across seven materials — steel and iron, galvanized steel, stainless steel, brass and bronze, aluminum, copper-nickel, and titanium — almost entirely in inch sizes (7,642 of 7,679 SKUs), with a small metric assortment (37 SKUs) mixed in. New to pipe fittings, or not sure whether you need a threaded or unthreaded connection? Use the filters below, or the comparison table, to narrow down by material, pressure rating, and thread type.
Compare Pipe Fitting Families by Material and Pressure Rating
| Category | Material | Connection | Pressure/Duty Tier | Watch Out For |
|---|---|---|---|---|
| Low-Pressure Iron and Steel Threaded Pipe and Pipe Fittings | Iron, Steel | Threaded | Low | The largest steel threaded family — general-purpose, not for high-pressure service |
| Medium-Pressure Iron and Steel Threaded Pipe and Pipe Fittings | Iron, Steel | Threaded | Medium | Includes fittings made specifically for joining dissimilar metals — check before pairing with copper or stainless |
| High-Pressure Iron and Steel Threaded Pipe and Pipe Fittings | Iron, Steel | Threaded | High | Extra-thick-wall nipples and SAE-style flanges — confirm wall thickness matches your rating, not just the size |
| Extreme-Pressure Steel Threaded Pipe and Pipe Fittings | Steel | Threaded | Extreme | Super-thick-wall construction — the top pressure tier in the steel line, not stocked in every size |
| Low-Pressure Galvanized Iron and Steel Threaded Pipe and Pipe Fittings | Galvanized Iron, Steel | Threaded | Low | Zinc coating protects against corrosion but is not rated for high-pressure or high-temperature service |
| Iron and Steel Unthreaded Pipe and Pipe Fittings | Iron, Steel | Unthreaded | Low–Extreme | Spans four pressure tiers plus FM-approved cast iron flanges for fire protection — verify certification if code requires it |
| Iron and Steel Clamp-On Pipe and Pipe Fittings | Iron, Steel | Grooved/clamp-on | — | Includes DWV (drain-waste-vent) iron pipe — no threading required, but grooves must match your coupling |
| Stainless Steel Threaded Pipe and Pipe Fittings | Stainless Steel | Threaded | Low & High | Spans both pressure tiers in one category — check the specific subcategory rating before ordering |
| Stainless Steel Unthreaded Pipe and Pipe Fittings | Stainless Steel | Unthreaded | Low & High | Same low/high split as the threaded line — confirm wall thickness for your application |
| Brass and Bronze Threaded Pipe and Pipe Fittings | Brass, Bronze | Threaded | Low – High | Includes plated and drinking-water-rated options — confirm plating/finish if the fitting will be visible or wet-rated |
| Brass and Bronze Unthreaded Pipe and Pipe Fittings | Brass, Bronze | Unthreaded | Low | Smallest of the brass and bronze families — limited to flanges and plain pipe |
| Aluminum Pipe and Pipe Fittings | Aluminum | Threaded & Unthreaded | Low | Lightweight but not pressure-graded the way the steel lines are — check load requirements before swapping in |
| Copper-Nickel Pipe and Pipe Fittings | Copper-Nickel | Threaded & Unthreaded | — | A small, seawater-resistant family — mainly for marine and desalination piping, not general plumbing |
| Titanium Threaded Pipe Fittings | Titanium | Threaded | — | The smallest and most specialized family — lead times may run longer than for steel or stainless |
| Pipe Collars | Steel, Stainless Steel | Clamp-on | — | Not a pipe fitting in the traditional sense — used to anchor or seal around a pipe passing through a wall or floor |
Threaded vs. Unthreaded Connections
Threaded pipe fittings connect using tapered pipe threads that wedge together as they're tightened, forming a seal without a separate gasket. Unthreaded fittings — plain-end, beveled, or flanged — are joined by welding, grooved couplings, or bolted flange connections instead, which is typically the choice for larger pipe sizes or permanent installations. Most of the steel, iron, and stainless steel families above stock both connection types; brass and bronze, aluminum, and copper-nickel are split the same way, while titanium is threaded-only.
Need a Custom Fitting or Pressure Rating?
Don't see the material, pressure rating, or size you need? Our team can cross-reference an existing fitting or quote a custom configuration. Request a Quote or Contact Us.
Frequently Asked Questions
What's the difference between threaded and unthreaded pipe fittings?
Threaded fittings screw onto pipe with matching tapered threads, making them easy to assemble, disassemble, or service without welding. Unthreaded fittings are joined by welding, grooved couplings, or bolted flanges, which generally hold up better at larger sizes and higher pressures but are harder to take apart.
What do the "Low-Pressure," "Medium-Pressure," "High-Pressure," and "Extreme-Pressure" tiers mean?
These tiers reflect the wall thickness and construction of the fitting, which determines the maximum pressure it can safely handle. A higher tier generally means a thicker-walled fitting rated for more demanding service, not a different size or thread standard.
Can I connect stainless steel or copper fittings directly to steel pipe?
Joining dissimilar metals directly can cause galvanic corrosion over time. Our Medium-Pressure Iron and Steel Threaded Pipe and Pipe Fittings category includes fittings designed specifically for transitioning between dissimilar metals — check there before connecting steel piping to stainless steel, brass, or copper-nickel.
Are LILY's pipe sizes measured in inches or metric?
The large majority of our stock — 7,642 of 7,679 SKUs — is sized in inches, following standard nominal pipe size (NPS) conventions. A smaller metric assortment (37 SKUs) is also available; use the System of Measurement filter to narrow to one or the other.
