What Is a Camlock (Cam & Groove) Coupling?
Camlock couplings—also called cam & groove fittings—are quick-connect fittings used to join hoses and pipes in liquid, gas, and dry-bulk transfer applications. Two couplings, a standard-body coupler (female socket) and an adapter (male plug), lock together with a quarter-turn cam action: press the arms down, insert the adapter, and release—no tools required. That speed makes them indispensable on tanker trucks, chemical processing lines, fuel transfer rigs, irrigation systems, and fire suppression circuits.
The Seven Standard Types
The standard types (A through F, plus DC/DP dust caps and plugs) were originally defined by MIL-C-27487 (now superseded by A-A-59326). Each type is either an adapter (male cam groove end) or a coupler (female cam-arm socket end), paired with a second connection. Knowing the type you need before you order prevents mis-matched pairs.
| Type | Cam end | Other end | Most common use |
|---|---|---|---|
| A | Male adapter (groove) | Female NPT thread | Adapt a threaded pipe/manifold into a camlock line |
| B | Female coupler (cam arms) | Male NPT thread | Couple onto an adapter; threads into a fitting or valve |
| C | Female coupler (cam arms) | Hose shank / barb | Hose end that connects to an adapter |
| D | Female coupler (cam arms) | Female NPT thread | Couple a threaded outlet (e.g., tank valve) to an adapter |
| E | Male adapter (groove) | Hose shank / barb | Hose end that connects to a coupler |
| F | Male adapter (groove) | Male NPT thread | Adapter that threads into a female pipe port |
| DC / DP | Dust cap (fits over adapter) / Dust plug (fits into coupler) | — | Protects open ends during storage and transport |
Quick memory aid: B, C, D are couplers (female cam arms); A, E, F are adapters (male groove).
Sizing: How to Pick the Right Diameter
Camlock sizes run from ½" through 6" (nominal). The nominal size refers to the inner diameter of the coupler body, which controls flow capacity. As a rule of thumb, match the camlock size to your hose's inside diameter. When transferring viscous fluids (hydraulic oil, molasses, slurry) or abrasive media, consider going one size up to reduce friction losses.
- ¾" – 1½": light chemical, agricultural spray, fuel dispense
- 2" – 3": industrial liquid transfer, tanker truck loading/unloading
- 4" – 6": bulk product, high-volume water and petroleum transfer
Dura-Line's 1.25" Shur-Lock II coupler (item 20000120) is a common 1¼" example for light industrial runs. We also carry specialty configurations such as the Dixon Valve 200YDAAAL — a 2" aluminum cam & groove wye (coupler × adapter × adapter) for splitting one line into two — and the Civacon/OPW 633D-SS10, a 1" stainless Type D (female coupler × female NPT).
Browse all available couplings and plumbing fittings in our Hydraulics, Pneumatics & Plumbing collection.
Material Selection: Aluminum vs. Stainless vs. Polypropylene
| Material | Best for | Avoid with | Weight | Cost |
|---|---|---|---|---|
| Aluminum | Petroleum fuels, water, compressed air, mild chemicals | Acids, alkalis, seawater | Light | $ |
| 316 Stainless | Acids, caustics, food grade, corrosive environments, coastal/marine | Concentrated chlorides at elevated temp | Medium | $$$ |
| Brass | Potable water, natural gas, non-oxidizing acids | Ammonia, acetylene, amines | Heavy | $$ |
| Polypropylene | Dilute chemicals, slurries, agriculture | Aromatic solvents, ketones, oxidizers | Lightest | $ |
We stock both aluminum (Dixon Valve) and stainless steel (Civacon/OPW) camlock fittings. See available camlock fittings →
Gasket & Seal Material
The internal gasket is the most failure-prone component. Match the gasket material to your fluid:
- Buna-N (NBR) — petroleum products, water (most common default)
- EPDM — hot water, steam, dilute acids, many chemicals
- Viton (FKM) — aggressive solvents, concentrated acids, high temps
- PTFE/Teflon — ultra-pure water, strong oxidizers
Pressure Ratings
Camlock pressure ratings decrease with size. For a 2" aluminum camlock the typical working pressure is 150–250 PSI; a 4" unit may be rated as low as 75 PSI. Never rely on the nominal thread rating of the attached pipe—always check the camlock's published WP at your operating temperature. Surge pressure (water hammer) can spike 2–3× steady-state; install a surge-protection valve on liquid systems wherever possible.
Inspection Checklist Before Use
- Check cam arms for cracks, deformation, or missing roll pins
- Inspect the gasket for cuts, hardening, or chemical attack
- Verify the cam arm groove in the adapter is clean and not worn oval
- Confirm body threads (if any) are clean and undamaged
- Test-connect and tug firmly before pressurizing