1BH Adapter: BSP Male Double Use with Metric Male L-Series End

The 1BH adapter is a hydraulic adapter that joins a British Standard Pipe port to a metric O-ring port. One end is a double use BSP male stud end that seals either on a 60 degree cone seat or on a flat face with a bonded seal washer. The other end is a metric male stud end to ISO 6149-3, light duty L series, sealed by an O-ring at the face of the thread. The BSP side is BSPP (G thread) to ISO 228-1. HENGHUA produces the range in carbon steel with zinc plating, in 304 and 316 stainless steel, and in brass.

1. What a 1BH Adapter Does

Imported machinery often mixes thread systems: a British Standard Pipe port on one component and a metric port to ISO 6149-3 on another, on the same hydraulic line. The 1BH adapter bridges the two without an additional reducing bush. Its BSP stud end is the familiar double use design, sealing on a 60 degree internal cone or on a flat face with a bonded seal washer. Its metric end seats an O-ring against the face of the metric port, which is the seal arrangement specified for light duty L series stud ends.

Because the two ends belong to different standards, the part number states both thread sizes, and the O-ring code for the metric end is given in the chart so the correct ring can be ordered with the adapter or replaced later.

2. Specifications

2.1 Connection 1

Connection 1 is the double use BSP male stud end.

• Thread form: BSPP (G thread) to ISO 228-1, parallel, 55 degree thread form, stated as size and threads per inch, for example G1/4″X19.
• Port end geometry: 60 degree internal cone seat combined with a flat face for a bonded seal washer.
• Sealing options: 60 degree cone seat or bonded seal washer on the flat face.
• Sizes in the series: G1/8″X28 through G1.1/2″X11.

2.2 Connection 2

Connection 2 is the metric male stud end to ISO 6149-3, light duty L series.

• Thread form: metric parallel thread with a 1.5 mm or 2 mm pitch depending on size, for example M12X1.5, M18X1.5, M22X1.5 and M27X2.
• Sealing method: O-ring seated at the face of the thread against the metric port face, identified in the chart by an O-ring code such as O13-3X2.4.
• Standard: ISO 6149-3, light duty, L series, metric ports and stud ends with O-ring sealing.
• O-ring material: NBR, FKM or EPDM, selected to the order.
• Configuration: straight, both connections on one axis.

2.3 Construction and Materials

• Carbon steel body with zinc plating as standard.
• Trivalent chromium zinc (Cr3+) plating and zinc-nickel plating as available options.
• 304 stainless steel and 316 stainless steel for corrosive and marine duty.
• Brass bodies where a non-ferrous part is required.
• O-rings in NBR, FKM or EPDM.
• Both stud end seats, the BSP cone and flat face and the metric O-ring seat, are machined to the drawing.

2.4 Pressure and Temperature

Working pressure is not a single value for the series. It is set by the connection size, the wall thickness of the body and the sealing method, and HENGHUA engineering confirms the working pressure for each ordered size and seal combination on the order.

Temperature follows the elastomer:

• NBR: approximately -30 C to +100 C.
• FKM: approximately -20 C to +200 C.
• EPDM: approximately -40 C to +120 C.

The assembly is limited by the lower of the metal and elastomer figures.

2.5 Part Number and Dimension Table

The table below is reproduced from the published series chart. Dimensions are in millimetres.

Chart note: E is the double use BSP male stud end and F is the metric male L series stud end to ISO 6149-3. A, B and L are lengths in millimetres as defined on the series drawing, S1 is the hex across flats and the O-ring code names the ring that fits the metric end. Every 1BH adapter in the range is supplied to these dimensions. The three S1 cells marked [VERIFY WITH SUPPLIER] could not be confirmed at the available chart resolution and must be checked against the current drawing before ordering.

3. How to Read a 1BH Part Number

• 1BH is the series code: BSP male double use for 60 degree seat or bonded seal, with a metric male L series end.
• The first number pair is the E thread, the BSP double use stud end.
• The second number pair is the F thread, the metric stud end to ISO 6149-3. Sizes are given in whole millimetres, for example 16 for M16X1.5.

Examples:

• 1BH-08-18: E end G1/2″X14, F end M18X1.5 with O-ring O15-3X2.4.
• 1BH-12-22: E end G3/4″X14, F end M22X1.5 with O-ring O19-3X2.4.
• 1BH-20-42: E end G1.1/4″X11, F end M42X2 with O-ring O38.5X3.0.

4. Installation and Fitment

1. Identify which side of the assembly is the BSP port and which is the metric port. The two threads are close in appearance on small sizes and are not interchangeable.
2. Check the O-ring on the metric end before fitting. Replace any ring that is cut, swollen or hardened.
3. Confirm the sealing method at the BSP end: 60 degree cone or flat face with a bonded seal washer.
4. Clean both ports. The metric end seals on the port face, so a burr or a trace of old sealant on that face will cause a leak.
5. Lubricate the threads lightly with a hydraulic-system-compatible compound so the O-ring is not rolled out of its seat.
6. Start both ends by hand. Never force a metric nut onto a BSP thread or the reverse.
7. Tighten on the hex to the torque that suits each thread size and the port material, holding the adapter body so the first joint is not disturbed.
8. Pressurise and check both joints before returning the machine to service.

5. Applications and Industries

• Imported construction and earthmoving machinery with mixed thread systems.
• Agricultural and forestry equipment built to more than one standard.
• Material handling and lifting plant.
• Mining and quarry hydraulic circuits.
• Marine and offshore deck machinery.
• Hydraulic power units and test benches built with metric porting.
• Industrial machine tools and presses.
• Service workshops that repair mixed-fleet equipment.

6. Replacement and Cross-Reference Guide

Cross-reference by standard, thread and sealing method only.

When replacing a metric to BSP adapter, confirm the metric port series as well as the thread size. A light duty L series port and a heavy duty S series port take different stud ends even when the thread is nominally the same size.

7. Ordering, Packaging and Delivery

Give the following details with the order:

• Part number, for example 1BH-12-22.
• Quantity.
• Body material: carbon steel, 304 stainless, 316 stainless or brass.
• Plating option: standard zinc, trivalent chromium zinc (Cr3+) or zinc-nickel.
• O-ring elastomer for the metric end: NBR, FKM or EPDM.
• Spare O-rings if required, quoting the O-ring code from the chart.
• Drawing, marking or private label requirements.

Adapters are packed in bulk cartons and shipped on pallets or in export crates, and packaging can be labelled to the buyer’s specification. Delivery is confirmed on the order acknowledgement, together with the working pressure confirmed by HENGHUA engineering for the ordered size and seal combination.

8. FAQ

What is a 1BH adapter used for? It connects a British Standard Pipe port to a metric port to ISO 6149-3 in the same hydraulic line. The BSP end is a double use stud end and the metric end is an L series stud end with an O-ring.

Which metric standard does the metric end follow? ISO 6149-3, light duty, L series, with O-ring sealing at the face of the port. It is the light duty series, not the heavy duty S series.

How does this adapter differ from the 1B version? The BSP double use stud end is the same. The difference is at the other end, which is metric rather than BSP, so the adapter bridges two thread systems.

Which O-ring does the metric end use? The chart gives a code for each size, for example O13-3X2.4 for M16X1.5. Quote that code and the required elastomer when ordering spare rings.

What is the working pressure? It depends on the connection size, the body wall thickness and the sealing method at each end. HENGHUA engineering confirms the figure for each ordered size and seal combination.

Which O-ring materials are available? NBR for general hydraulic oil service, FKM for higher temperatures and EPDM where the circuit requires it. Approximate service ranges are NBR -30 C to +100 C, FKM -20 C to +200 C and EPDM -40 C to +120 C.

Which body materials are available? Carbon steel with zinc plating as standard, with trivalent chromium zinc and zinc-nickel plating options, and bodies in 304 stainless steel, 316 stainless steel or brass.

Can it be fitted to a tapered BSPT port? No. A BSPT port to ISO 7-1 requires a taper thread that seals on the thread. Use a taper thread series for that port type.

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