A camlock looks like the simplest fitting on the hose rack: two halves, two arms, done. That is exactly why it gets specified carelessly. The part number tells the factory the type, the size and the body material — and leaves out the three things that most often decide whether the joint works: the thread standard, the gasket and the pressure rating at that size.
This guide takes the decisions in the order you have to make them, and flags the mistakes we see most often on camlock enquiries.
The five decisions, in order
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Decide which half you need — coupler or adapter
Every cam and groove joint is one coupler (the female half that carries the cam arms) and one adapter (the male half with the groove). Look at what is already fitted on the tank, pump or hose you are connecting to. If it has a groove, you need a coupler. If it has arms, you need an adapter.
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Pick the type letter from what is on the other end
The letter describes the end that is not the cam connection: a female thread, a male thread or a hose shank. It has nothing to do with size or material.
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Confirm the size and the thread standard
Camlock size is a nominal pipe size, from 1/2″ to 6″ (DN15 to DN150). On threaded types you also need the thread standard — BSP or NPT. The two are not interchangeable.
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Choose the body material and the gasket together
The body is chosen for the fluid and the environment. The gasket is chosen for the fluid. A good body with the wrong gasket still leaks.
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Check the pressure rating at that size
Working pressure falls as the bore gets larger. A 2″ metal camlock and a 6″ metal camlock do not carry the same rating.
Step 2 in detail: camlock types A to F, DC and DP
Read the table from the left. Once you know whether you need a coupler or an adapter, the other end tells you the letter.
| Type | Cam half | Other end | Typical use |
|---|---|---|---|
| A | Adapter | Female thread | Screws onto a threaded male pipe end |
| B | Coupler | Male thread | Screws into a threaded female port |
| C | Coupler | Hose shank | Hose end, clamped or crimped |
| D | Coupler | Female thread | Screws onto a threaded male fitting |
| E | Adapter | Hose shank | Hose end, clamped or crimped |
| F | Adapter | Male thread | Screws into a threaded female port |
| DC | Dust cap | — | Closes an adapter when disconnected |
| DP | Dust plug | — | Closes a coupler when disconnected |
A hose with a Type C at one end and a Type E at the other can be joined to an identical hose, which is why C and E are the usual pair for hose lines. Order DC caps and DP plugs at the same time: an open camlock left on the ground collects grit in the groove, and grit is what wears the gasket face.
Step 3 in detail: size and thread
Camlocks built to MIL-C-27487 / A-A-59326 dimensions interchange across brands at the same nominal size, so a 2″ Sunze coupler will close on a 2″ adapter from another maker. What does not interchange is the thread on types A, B, D and F.
BSP and NPT threads look alike and, in 1/2″ and 3/4″, share the same number of threads per inch. A BSP Type B will start into an NPT port and feel right for a turn or two. It will not seal. If your plant is in North America, the port is almost certainly NPT; across the UK, Australia, much of Asia and the Middle East it is usually BSP. When in doubt, measure the thread form — 55° for BSP, 60° for NPT — or send us a photo of the port.
For hose-shank types C and E, the size that matters is the hose bore. The shank goes inside the hose; the clamp or ferrule goes over the outside, so you will also need the hose outside diameter when you choose the clamp. Our T-bolt clamp sizing guide explains how to measure it.
Step 4 in detail: body material and gasket
Any body material mates with any other of the same type and size, so it is tempting to treat aluminium, stainless, brass and polypropylene as four price points for one part. They are four different failure modes.
| Body | Choose it for | Avoid it for |
|---|---|---|
| Aluminium | Water, compressed air, dry bulk and fuel transfer. The lightest metal option. | Strong alkalis and several chlorinated solvents. |
| 316 stainless | Chemical, food and beverage, marine and offshore duty. | Warm lines carrying chlorides, where stress-corrosion cracking becomes the risk. |
| Brass | Hydrocarbons, solvents, mild acids and agricultural chemicals. Non-sparking. | Anything containing ammonia or amines. |
| Glass-filled PP | Aggressive chemicals at ambient temperature, at a fraction of the weight. | Non-conductive flammable liquids without separate bonding; hot service. |
The gasket is where most field failures actually start. NBR (Buna-N) is the default on almost every camlock shipped, and it is the right choice for petroleum oils and fuels. EPDM is close to its opposite: good on ketones, many acids and hot water, destroyed by petroleum oil. FKM covers aggressive solvents and higher temperatures; PTFE-encapsulated seals cover what nothing else will. If the fluid is anything other than water, air or dry bulk, write the gasket into the purchase order.
The full material comparison, including the 304 versus 316 series and the handle and pin materials, is on our camlock fittings page.
Step 5 in detail: pressure rating by size
The cam arms hold a sealing face against the line pressure. A larger face sees a larger force, so the rating falls as the size goes up.
| Size | Metal bodies | Glass-filled PP |
|---|---|---|
| 3/4″ – 1-1/2″ | 250 psi | 125 psi |
| 2″ | 250 psi | 100 psi |
| 2-1/2″ | 150 psi | — |
| 3″ | 125 psi | 100 psi |
| 4″ | 100 psi | — |
| 5″ – 6″ | 75 psi | — |
These are working pressures at ambient temperature, with a gasket that suits the fluid and both arms fully closed. Polypropylene loses strength as temperature rises. For 1/2″, or any duty above ambient, ask us for the figure against your actual combination.
Where a camlock is the wrong fitting
- Steam. A cam arm can be knocked open, and the standard gasket materials are not steam materials. Use a fitting designed for steam service, with a DIN 2817 safety clamp on the hose end.
- Compressed gas at pressure. Stored gas energy released by an arm opening is a different hazard from a liquid line losing pressure.
- Unattended pressurised lines. Fit locking arms or safety pins, or use a bolted connection.
- Fire service and municipal water. Many fire services standardise on Storz couplings, which are symmetrical — there is no male or female half. If you are connecting to fire or municipal equipment, check which system it uses before you order. We make Storz couplings as well, including aluminium Storz lug couplings.
Before you send an enquiry
Send these six things and you will get a quotable answer first time:
- Type letter for each item (A, B, C, D, E, F, DC or DP)
- Nominal size, 1/2″ to 6″
- Thread standard on threaded types — BSP or NPT
- Body material, or the fluid if you would like us to recommend one
- Gasket material, or the fluid it will see
- Quantity per item, and whether you need locking arms, safety pins or chains
A photo of the existing port or fitting answers most thread questions in one go.
Send us your camlock list
We will check the types, threads and gaskets against your duty and come back with a factory quotation within 24 hours. ISO 9001 manufacturing in Taiwan since 1976, OEM and private label welcome.
Request a quotation