Metric Female Adapter 5CM / 5DM (Metric Female 24° Cone Seat to Metric Male Cone Stud)

Why This Metric Female Adapter 5CM / 5DM Gives You a Female Connection Where the Port Cannot Move

The metric female adapter 5CM / 5DM is a straight adapter whose defining connection is a metric female thread with a 24° cone seat. That seat is what receives a male 24° cone stud. The second connection carries the adapter back into the tube system, and the result is a compact transition wherever a male stud has to land on a female seat that is not on the port you are working with.

The reason a female connection is worth a dedicated part is simple. A male stud end on a hose or tube assembly can only be threaded into a female seat. If the port in front of you is itself a male stud, or the run has to arrive from a direction the port does not face, the assembly needs an interface that presents a female seat in the right orientation. The metric female adapter 5CM / 5DM is that interface, and it keeps the whole joint inside the 24° cone system rather than introducing a second sealing principle.

Within the metric female adapter 5CM / 5DM family, the letters identify the series: 5CM is the light L series preparation and 5DM is the heavy S series preparation. Both are the same fitting in two wall thicknesses and thread proportions, matched to the components they are designed to accept.

Core Advantages

1. A true female 24° cone seat — the joint seals at the cone face, so a male stud seats and seals exactly as it would in a port, without a tapered thread or a bonded washer.
2. RN option for elastomeric sealing — where the drawing calls for an O-ring assisted seat, the RN suffix version supplies the female connection with an elastomer ring in the seat; see the RN suffix note below.
3. One-piece machined body — no brazed joints and no internal assembly threads, so the only leak path is the designed cone contact.
4. Compact straight envelope — the adapter adds length, not width, which matters where wrench access is limited to the axis of the port.
5. Light L and heavy S series from one drawing set — 5CM and 5DM cover both port standards, so a mixed-standard machine stays on one spare-parts line per size.
6. Free cross-reference and 24-hour quotation — send the drawing, the old part number or a photograph and we will confirm the series, the seat form and the suffix that applies.

Technical Specifications

What Is a Metric Female Adapter?

A metric female adapter is a fitting whose primary connection is an internal metric thread with a 24° cone seat machined into it. When a male 24° cone stud is threaded in and torqued, the cone is pressed into the seat and the two steel surfaces seal metal-to-metal. If the part number carries the RN suffix, an elastomer ring is also present in the seat, and the joint then seals on both the cone and the ring.

This is the same interface family used throughout DIN 3861 / ISO 8434-1 tube systems, which is why the metric female adapter 5CM / 5DM can be fitted into an existing tube run without changing the tools, the torque values or the port preparation already in use on the machine.

Connection 1 — Metric Female 24° Cone Seat (Defining Connection)

Connection 2 — Line End

The second connection of the standard metric female adapter 5CM / 5DM is a metric male 24° cone stud end, so the fitting couples a male stud to a female port in one part. Where your drawing shows a female thread at both connections, or a stepped thread pair, the adapter is produced to order from the same body stock.

Dimensional Data

Full Part Number Matrix

The table above is transcribed in full from the 5CM / 5DM drawing: 10 light series L rows and 10 heavy series S rows, each carrying both threads (E female 24° cone seat, F male line connection), the tube outside diameter D1, the dimensions B, l1 and L1, the hexes S1 and S2, and the pressure grade printed against that row.

RN Suffix Note

Part numbers with the RN suffix are supplied as a complete set with the cutting ring and nut for the tube end. The version without the suffix is the adapter on its own; both versions seal metal-to-metal on the 24° cone, and neither uses an elastomeric seat insert.

Four practical points follow from that footnote:

1. The sealing mechanism changes, the thread does not. An RN version and a plain version of the same size share the thread and the hex; only the seat preparation and the presence of the ring differ.
2. Do not add an O-ring to a plain seat. The ring has to sit in a machined groove. Pressing one into a plain cone seat moves the cone off its seat and creates a leak path rather than closing one.
3. Choose RN where the mating surface is less than perfect. An O-ring backed seat forgives minor surface marking, which is why it is often specified on repair work and on equipment that is dismantled repeatedly.
4. Order the suffix explicitly. Because both versions exist under one base number, always state “plain” or “RN” on the enquiry so that the correct seat is machined and the correct part number is marked on the fitting.

Where the seat form is critical — for example on a manifold with a machined cone recess or a machine that has been converted from one standard to the other — send the port drawing with the enquiry and we will confirm which suffix the joint requires.

Materials and Finish

Working Pressure and Operating Envelope

The working pressure of a metric female adapter 5CM / 5DM depends on the thread size, the series, the material and wall thickness of the mating stud and port, and the operating temperature. The female connection transmits the same load as a port seat of the same size, so the limit is normally set by the port or the stud rather than by the adapter. Light L series parts belong with light series components and heavy S series parts with heavy series components; the two are not interchangeable even where a thread starts.

On the RN version the elastomer in the seat adds a temperature and fluid-compatibility limit that the plain version does not have. Nitrile is the standard compound, and alternatives are available where the fluid or the ambient temperature rules nitrile out. Request the size-specific pressure table with your enquiry and we will return the rating for the exact thread, series and seat form.

Installation Notes for the 5CM / 5DM Adapter

1. Confirm the suffix before assembly. Check whether the seat should be plain or RN, and check that the fitting in your hand matches the drawing.
2. Inspect the seat. Look for dirt, burrs or a previous thread sealant. On a plain seat the cone must be able to fully contact the seat face; on an RN seat the ring must be undamaged and correctly seated in its groove.
3. Fit the line end first. Make up Connection 2 to its specified torque, so the adapter is fixed before the female connection is loaded.
4. Start the male stud by hand into the female seat until the cone contacts the seat face. Never start a cone joint with a wrench.
5. Torque to the value for the thread size and the material of the stud. Over-torquing a female seat distorts the cone face and is not recoverable.
6. Pressure-test the joint before the machine returns to service, particularly where an RN seat has been used on a dismantled and reassembled line.

Applications

The metric female adapter 5CM / 5DM is specified wherever a female 24° cone seat has to be presented to a male stud that cannot reach the port directly:

• Machine tools and test stands with pre-bent tube runs that arrive at the wrong orientation
• Manifolds and valve blocks where a stud has to be coupled to a remote female interface
• Mobile and agricultural equipment repaired in the field, where the correct interface may not exist on the machine
• Equipment converted between light and heavy series tube standards
• Service kits that have to cover several thread sizes with the smallest possible number of components

In each case the objective is the same: create the female seat where it is needed, without leaving the 24° cone system.

Quality, Testing and Traceability

Every metric female adapter 5CM / 5DM is machined from controlled steel stock, and thread form, seat angle, seat depth and hex squareness are checked as part of the normal production flow. Sizes are pressure tested on sample basis, batch labels allow a supplied adapter to be traced back to the material lot, and material test reports, dimensional inspection records and third-party inspection arrangements are available on request. OEM laser marking of part numbers or customer references can be applied where the quantity supports it.

Ordering Information

To order, specify five things:

1. Series — light L (5CM) or heavy S (5DM)
2. Female thread size — the 24° cone seat dimension at Connection 1
3. Second connection — standard male 24° cone stud, or a female or stepped version to order
4. Suffix — plain seat or RN (O-ring assisted seat)
5. Quantity and marking — including any customer reference that has to be laser marked

Standard catalogue sizes ship from stock with plain or RN seats as ordered; non-standard thread pairs are machined to order.

FAQ

What does RN mean on this part number? It indicates that the female 24° cone seat is supplied with an elastomeric O-ring. The plain version seals metal-to-metal on the cone alone. See the RN suffix note.

Can I fit an O-ring into a plain seat myself? No. The plain seat has no groove for a ring, and adding one lifts the cone off its seat.

Is the metric female adapter 5CM / 5DM a swivel fitting? No. The female connection is machined into the body. Where a free-turning nut is required, a different adapter family is used.

Which series should I order, 5CM or 5DM? Match the series of the stud and the tube assembly you are connecting. A light series seat with a heavy series stud is not a valid joint even if the thread appears to start.

Can you supply the matching male 24° cone studs? Yes. Mating studs, union nuts and complete tube assemblies are available on the same order.

Request a Quote for the Metric Female Adapter 5CM / 5DM

Send us the port drawing, the mating stud part number, or a photograph of the fitting being replaced, and we will confirm the series, the thread, the seat form and the suffix within 24 hours. Please state whether the seat should be plain or RN, and include the working pressure, the fluid and the operating temperature so that we quote the correct material and elastomer. Non-standard thread pairs, stainless steel bodies and complete tube assemblies are available on the same order.

Browse the full Hydraulic Adapters range for the complete family, or contact us to request a quote, mill test reports, and samples.