7B9-PK Adapter – 90° Elbow BSP Female ISO 1179 Hydraulic Adapter

1. What a 7B9-PK Adapter Does

A 7B9-PK adapter is a 90° elbow hydraulic adapter with a BSP female end made to ISO 1179 at both ports. It joins two BSP male stud ends that would otherwise have to meet in a straight line, and it turns the connection through a right angle.

Both ends must match their mating stud ends exactly, in thread form, seat geometry and hex clearance, because a correct match at both ends is the precondition for eliminating leakage at the conversion point.

Each port seals on an internal 60° cone seat that receives the matching male cone, following the ISO 228-1 thread form and the ISO 1179 seat geometry. The thread provides clamping force only.

2. 7B9-PK Adapter Specifications

2.1 Connection 1 – BSP female, ISO 1179 (port E)

Port E is a BSPP female end dimensioned to ISO 1179, offered from G1/8″x28 to G2″x11. ISO 1179 covers ports and stud ends with ISO 228-1 threads in the BSPP family, including the 60° cone seat configuration, so a stud end produced to that standard makes up correctly in this port.

The joint is metal to metal at the cone and needs no separate sealing element, which keeps the connection compact and lets it release cleanly for service.

2.2 Connection 2 – BSP female, ISO 1179 (port F)

Port F mirrors port E: a BSPP female end dimensioned to ISO 1179, from G1/8″x28 to G2″x11. The two legs of a same-size part number are machined to the same seat geometry, and the chart below shows equal A and B values for those rows.

This is the female-to-female configuration of the elbow, which is the reason for the -PK suffix in the part number. On this series the suffix must be quoted in full: 7B9 alone describes a different family in the British Adapters range.

2.3 Construction and Materials

The body is machined from bar stock on CNC lathes, with the 90° bend and both female ISO 1179 ends produced in one part. Threads are gauged and both internal cones are inspected for a full contact form before packing.

• Body material options: carbon steel, 304 stainless steel, 316 stainless steel, brass.
• Plating options: trivalent chromium zinc plating (Cr3+), or zinc-nickel plating for more aggressive environments.
• Seal options: the cone joint needs no separate seal, and no bonded seal or O-ring is fitted at either port of this series.
• Hex flats at both legs are dimensioned on the drawing so each end can be tightened with a wrench.

2.4 Pressure and Temperature

Working pressure is not a single figure for the series. It depends on the thread size, the wall thickness at the elbow and the body material. Working pressure for these sizes is confirmed per order by HENGHUA engineering, based on the thread size and material selected.

Because the 7B9-PK uses cone joints, the seal material question belongs to the mating stud ends rather than to this part. Where a bonded seal or an O-ring is used elsewhere in the same assembly, these material ranges apply:

Carbon steel with zinc plating suits general hydraulic service. Choose 304 or 316 stainless steel where the adapter sees moisture, washdown or corrosive media.

2.5 Part Number and Dimension Table

All values are millimetres. Thread designations follow ISO 228-1. Column A is the leg dimension at port E, column B is the leg dimension at port F, and S1 is the hex dimension of the drawn wrench feature.

The chart above reproduces the full 7B9-PK range. The A value for 7B9-06PK is marked [VERIFY WITH SUPPLIER] because it could not be read unambiguously from the source chart; the B and S1 values for that row are as published. Confirm the A dimension for the 3/8″ size with HENGHUA engineering before you release a drawing-critical order.

3. How to Read a 7B9-PK Part Number

A 7B9-PK part number has three elements: the series prefix, the elbow code, and the configuration suffix.

• 7 – the BSP female ISO 1179 family in the British Adapters range.
• B – BSP thread, here BSPP to ISO 228-1.
• 9 – the 90° elbow version. The same family is supplied as a straight adapter, series 7B.
• PK – the female-to-female configuration marker used in the British Adapters range. It must be quoted with the part number.
• Size code – two digits giving the nominal thread size in sixteenths of an inch: 02 is 1/8, 04 is 1/4, 06 is 3/8, 08 is 1/2, 12 is 3/4, 16 is 1, 20 is 1.1/4, 24 is 1.1/2, 32 is 2.

Worked example: 7B9-12PK. Port E and port F are both G3/4″x14 female ends to ISO 1179 (code 12). From the chart, A and B are 34 mm and the hex S1 is 33 mm. This is the part to order when two male cone stud ends on a 3/4 inch circuit have to meet around a corner.

Note the hyphen inside the series code. Writing 7B9 without the -PK identifies a different item, so quote the part numbers exactly as they appear in the chart.

4. Installation and Fitment

Both ends of the 7B9-PK are female cone seats. Each joint is completed by a male stud end carrying the matching 60° cone, so bring the stud end in by hand, confirm that it turns smoothly for the first turns, then tighten with a wrench until the cones seat.

• Do not use thread sealant or tape, because the joint seals on the cone and not on the thread flanks.
• Fit the mating stud end to the hose or tube first, then make up the connection into the elbow, so the hose is not twisted during tightening.
• Keep both internal cones clean and free of swarf, paint or old sealant before assembly.
• Set the elbow direction before final tightening, since turning the body afterwards can score a seated cone.

Common fitment errors and the symptoms they cause:

A 7B9-PK adapter may be reused if the internal cones, the threads and the hexes are undamaged. Replace the mating stud ends if they show a pitted or broken contact ring.

5. Applications and Industries

Application tags: hydraulic systems, industrial equipment, construction machinery, agriculture, material handling, oil and gas, marine, water jetting.

5.1 Why an elbow instead of a straight adapter

A 90° elbow changes the direction of the connection at the port. Where both ends are female, the routing benefit and the access benefit usually decide the choice.

Routing in a tight envelope: the space in front of a manifold, pump or valve port is often occupied by another component. The elbow turns the line away immediately, so the hose or tube leaves parallel to the machine surface instead of projecting into free space.

Protecting the hose bend: a hose that leaves a port along the port axis and then has to bend sharply behind the machine is bent at a radius smaller than its design allows. The elbow removes that bend from the assembly.

Respecting the minimum bend radius: every hose has a minimum bend radius below which the reinforcement is stressed and service life falls. Moving the direction change into a machined steel elbow lets the hose run at a radius it was designed for, which matters most on the larger sizes in this range where the hose is stiff.

Access and service: with both ends female, the wrench works on the elbow hex rather than on a nut that faces a wall. On buried ports this is often the reason this elbow is selected over a straight adapter at all.

Fluid-dynamic trade-off: a 90° elbow adds a local pressure loss that a straight adapter does not have, because the flow must turn and the turn creates turbulence. Keep the bore matched to the hose and tube bore, avoid stacking several 90° elbows in one short run, and use a swept or larger-bore elbow where the circuit is sensitive to pressure loss. On return, pilot and gauge lines the loss is normally accepted in exchange for the routing and access benefit.

5.2 Concrete applications

Cross-standard equipment integration: a machine with BSPP ports is linked to a line built around a different port standard, and the female ISO 1179 ends accept the stud ends the line already uses.

Repair and replacement: when a male stud end or a hose end fails, the female-to-female elbow restores the connection on both sides in one step and keeps the existing routing.

High-pressure test benches: elbows hold hoses clear of the bench frame and out of the operator’s working area, and they let several lines leave one manifold with parallel runs.

OEM assembly lines: a fixed 90° geometry gives every unit the same routing, shortens the hose used, and removes the assembly step where a straight fitting has to be bent by hand.

6. Replacement and Cross-Reference Guide

Identify a replacement by standard and sealing method, never by brand. Three checks settle the identity of the part:

1. Thread: measure the outside diameter over the thread and count the threads per inch, then match to ISO 228-1 (BSPP, parallel, G) or ISO 7-1 (BSPT, taper, R and Rc). Pitch differs between the families, so a caliper plus a thread gauge is more reliable than a visual match.
2. Seat: confirm the seat at each connection, 60° cone to ISO 1179, flat face for a bonded seal, 37° flare to SAE J514, 74° seat, or an O-ring port to ISO 6149-3 or ISO 11926-3. A 60° cone and a 37° flare both look conical but do not mate.
3. End configuration: confirm that both ends are female and that both are 60° cone seats to ISO 1179, because the same thread size is supplied in several male and female configurations.

Useful equivalences within the HENGHUA range:

If the mating stud ends are BSPT, order a BSPT female series rather than forcing a 7B9-PK adapter onto a taper thread.

7. Ordering, Packaging and Delivery

To place an order or ask for a quotation, send the following: series code (7B9-PK), the full part number including the PK suffix, the thread size at both ports, the body material and plating, and the quantity. State the mating stud end standard as well, so HENGHUA can confirm that the cone angle and seat geometry match the parts you already use. If you work from a drawing rather than a catalogue part number, send the drawing and HENGHUA will confirm the nearest standard part number or quote a special.

Packaging and delivery:

• Standard packing in polyethylene bags inside export cartons, with desiccant where the destination or the season requires it.
• Cartons labelled with part number, thread sizes, material, quantity and batch reference, so a distributor can place the box straight on a shelf.
• Bulk packing and kit packing are available for OEM line delivery.
• Samples are available for validation before a production order; state the quantity and the part numbers you want to test.
• Lead time is confirmed per order, because it depends on part number, material, plating and quantity.

Every batch is checked against the drawing with thread gauges before packing, and the dimensional values on this page are taken from the series chart.

8. FAQ

Q1. What is the difference between BSPP and BSPT, and can they be interchanged? BSPP is the parallel thread defined by ISO 228-1, where pressure tightness is not made on the thread itself. BSPT is the taper thread defined by ISO 7-1, where the joint seals on the thread flanks and needs a sealant. They are not interchangeable: a tapered male end damages a parallel female port, and a parallel male end will not seal in a tapered port.

Q2. What is the difference between a 60° cone seat and a bonded seal, and which should I choose? A 60° cone seat seals metal to metal on a machined cone and needs no separate sealing element. A bonded seal seals on a flat face, using a metal washer bonded to a rubber ring. Choose the cone when the port is machined with a 60° cone to ISO 1179, and the bonded seal when the port face is flat and the joint depends on the washer.

Q3. How do I identify the correct 7B9-PK size? Read the two ports, not the hose. Measure the thread outside diameter and count the threads per inch, then match to ISO 228-1 to get the G size. Both ends carry the same nominal size, so one code describes the whole part, for example 7B9-12PK for G3/4″x14 at both ends.

Q4. What seal material should I select for my fluid and temperature? The 7B9-PK seals on a 60° cone and does not contain a seal element, so the seal material is decided by the mating stud ends. Where bonded seals or O-rings are used in the same assembly, NBR suits mineral oil from approximately -30°C to +100°C, FKM approximately -20°C to +200°C, and EPDM water and steam service approximately -40°C to +120°C.

Q5. How is the working pressure of this adapter determined? Working pressure depends on the thread size, the wall thickness at the elbow and the body material, so the series has no single figure. Working pressure for the sizes you order is confirmed by HENGHUA engineering per order, based on the thread size and material you specify.

Q6. What is the minimum order quantity and can I get samples? Minimum order quantity depends on the part number, the material and whether the item is standard or special, and it is quoted with the price. Samples are available for validation, and a sample order can be placed before a production quantity so fit and routing can be checked on the machine.

Q7. What does the PK suffix mean on a 7B9-PK adapter? PK identifies the female-to-female configuration in the British Adapters range. On the 7B9-PK both ports are BSP female ends dimensioned to ISO 1179, and the suffix appears at the end of every part number in the series, as in 7B9-16PK. Quote the suffix in full when ordering.

Q8. How do I tell a 60° cone seat from a 37° flare seat? Look at the angle of the internal cone and at the mating part. A 60° cone seat is the BSPP cone joint of ISO 1179 and mates with a 60° male cone. A 37° flare is the SAE J514 JIC joint and mates with a 37° male flare. The angles are different, so the two do not seal against each other even when the thread sizes look similar.

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