1BM BSP Male to Metric Male Adapter, Double Use 60° Seat or Bonded Seal – 1BM Adapter

The 1BM adapter is a straight hydraulic conversion fitting that joins a BSPP (G thread) port to a metric (M thread) port in one machined body, with both ends built for double use. Each male stud seals either on an ISO 1179 60° cone seat against a mating cone or on a bonded seal against a flat face. HENGHUA cuts both thread forms to the published port standards, so the BSPP end and the metric end each match the port they are specified against, which is the precondition for eliminating leakage at the conversion point.

1. What a 1BM Adapter Does

A 1BM adapter connects a BSPP (G) threaded port to a metric (M) threaded port, or the reverse order of assembly, without changing the direction of flow. It is a rigid straight body, so it is chosen where the two ports already line up and only the thread families differ.

Both ends of this series are double use stud ends. A 60° cone seat seals metal to metal where the male cone meets the cone machined in the port, and no separate sealing element is needed. The same stud also seals on a bonded washer (Dowty-type) when the mating port has a flat face, with the washer compressed between the hex shoulder and the port face.

Because the sealing concept is available at both ends, one part number covers a conversion between a BSPP 60° port and a metric port, or between a flat-faced BSPP port and a metric port, subject to the port face condition at each side. The series covers metric sizes from M10X1 to M30X1.5 against BSPP sizes from G1/8″X28 to G1″X11. It is a BSP adapter at one end and a metric adapter at the other, and it works as a 60 degree seat adapter wherever the mating port has a cone.

2. 1BM Adapter Specifications

The specification is presented as two mirrored stud ends, so a buyer can read off which end goes to which port before ordering.

2.1 Connection 1 – BSPP male, double use for 60° cone seat or bonded seal

2.2 Connection 2 – Metric male, double use for 60° seat or bonded seal

Note on geometry: ISO 8434-6 covers the 60° cone stud end family that corresponds to a metric 60° cone port, and it is the metric counterpart of the BSPP 60° seat described in ISO 1179. The pitch of the metric end varies by size and is listed for every row in the table below, so the stud must be matched to the port by nominal diameter and pitch together.

2.3 Construction and Materials

2.4 Pressure and Temperature

Working pressure for this series is governed by the size, the body wall thickness, the sealing method used at each end and the material selected, and it is confirmed per order by HENGHUA engineering against the drawing. No single pressure figure applies to the whole series, so the rating is quoted with the quotation for the specific part number and material.

Seal material temperature ranges are material facts rather than ratings of the assembly: NBR approximately -30°C to +100°C; FKM (Viton-type) approximately -20°C to +200°C; EPDM approximately -40°C to +120°C. Carbon steel with zinc plating suits general hydraulic service; 304 and 316 stainless steel are specified for corrosive and offshore environments.

2.5 Part Number and Dimension Table

Column meanings: PART NO. is the ordering code; E is the BSPP (G) stud end; F is the metric (M) stud end; A is the length of the BSP stud end in mm; B is the length of the metric stud end in mm; L is the overall length in mm; S1 is the hex across flats in mm.

Table note: every row of the current chart for this series is reproduced above. The chart as supplied ends at 1BM-16-22; larger combinations in this family are quoted on request: [VERIFY WITH SUPPLIER] for sizes above G1″X11 or M30X1.5. All dimensions are in mm and are confirmed against the drawing for the exact part number at order stage.

3. How to Read a 1BM Adapter Part Number

The code has three blocks. 1BM is the series: BSP male double use for 60° seat or bonded seal, with a metric male end that is also double use. The first number after the prefix is the BSPP (G) size, counted in sixteenths of an inch. The second number is the metric thread nominal diameter in mm. The letter D is added where the metric end carries the 1.5 mm pitch variant of a size whose other row carries 2 mm pitch.

Worked example: 1BM-12-27D decodes as 1BM series, 12 = 12/16 in = G3/4″X14 on the BSPP side, 27 = M27 nominal diameter, and D = 1.5 mm pitch, so the metric end is M27X1.5. The chart gives A = 18.5 mm, B = 16 mm, L = 46.5 mm and hex S1 = 32 mm. The plain code 1BM-12-27 in the same size is the M27X2 version.

Size code reference from the table above: 02 = G1/8″X28, 04 = G1/4″X19, 06 = G3/8″X19, 08 = G1/2″X14, 10 = G5/8″X14, 12 = G3/4″X14, 16 = G1″X11. On the metric side the code is the nominal diameter, so 10 = M10X1, 12 = M12X1.5, 14 = M14X1.5, 16 = M16X1.5, 18 = M18X1.5, 20 = M20X1.5, 22 = M22X1.5, 24 = M24X1.5, 26 = M26X1.5, 27 = M27X2 or M27X1.5 with the D suffix, 30 = M30X2 or M30X1.5 with the D suffix.

4. Installation and Fitment

Preparation decides the result. Clean both port threads and faces, remove old sealant and any burrs, and confirm that a flat face is unmarked, because a bonded washer cannot bridge a scored or dented face. Blow out the line so no swarf reaches a cone seat, and check that both ports are the same size pair as the part number.

Assembly practice. Run each end in by hand first; if the stud binds after a turn or two, the thread family or the pitch is wrong, so stop rather than force it. Fit a bonded washer over the stud where a flat-faced port is used, then tighten to a snug, firm seat that compresses the washer without extruding it. Where a 60° cone seat is used, the seal is made on the cone and no washer is fitted. Tightening torque and angle are confirmed per order and per size by HENGHUA engineering.

Alignment and reuse. Support the hose or tube so the adapter does not carry bending load, and never use the hex at one end to jack the other end home. Bonded washers and O-rings are single-use items, so replace them whenever a joint is broken; the steel body can be refitted with a new washer if the threads and cones are undamaged.

Common fitment errors and symptoms: a worn or wrong-size washer shows as weeping at the hex shoulder; a cone end offered to a flat-faced port will not seal because the two sealing concepts do not meet; a metric stud of the right diameter but the wrong pitch starts by hand and then jams; and a BSPT male end turned into a BSPP port damages both threads, because a taper thread and a parallel thread are not interchangeable.

5. Applications and Industries

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

Cross-standard equipment integration. Machines built to European port practice and machines built to metric port practice are often bolted into one circuit; this series makes the junction where a BSPP port has to take a metric line, or the reverse.

Repair and replacement. Maintenance teams keep the series for breakdown work on mixed-standard machinery, because the double use stud end covers both a cone port and a flat-faced port in one part number.

High-pressure test benches. Test rigs mix BSPP manifolds with metric valve and instrument ports, and the rigid straight body holds position on a panel with less joint movement than a swivel fitting.

OEM assembly lines. For a new build the series can be supplied to a drawing with a fixed plating and seal choice, so the line receives one part number per junction instead of two conversion pieces.

6. Replacement and Cross-Reference Guide

Cross-reference this series by standard, thread and sealing method only, never by another maker’s catalogue number. Identify the two thread families on the part being replaced, then match the sizes and the pitch.

Measure these three things. First, the thread: measure the outside diameter of each male thread and count the threads per inch on the BSPP side, then match it to the G series such as G1/2″X14. On the metric side measure the outside diameter and determine the pitch with a thread gauge, because M27X2 and M27X1.5 look alike from a distance and must not be mixed. Second, the seat: look inside the port. A 60° cone means the stud seals on the cone; a flat face means it seals on a bonded washer. Third, the seal: measure the washer bore and outside diameter if a washer is present.

Replacement rules. A part with a 60° cone metric stud is replaced by the same nominal diameter and pitch from this series; if the metric port is a flat-faced port instead, the same series still applies because the stud end is double use. A BSPT (taper) end is not equivalent to this series, because the 1BM BSP end is a parallel G thread that seals on a cone or a face rather than on the thread flanks.

7. Ordering, Packaging and Delivery

To order, give the series code plus the full part number, the two thread sizes with pitch, the seal material, the plating and the quantity, for example: 1BM series, 1BM-12-27D, G3/4″X14 to M27X1.5, FKM seals, trivalent chromium zinc plating on carbon steel, 1000 pieces. State which end faces the 60° cone port and which faces a flat face if the two are not the same, and send the port drawings if the geometry is unusual.

Packaging. Parts are packed in cartons with the part number and quantity labelled, in bulk or in poly bags as the order requires, and can be labelled for distributor shelves or for direct-to-line OEM delivery. Mixed-size cartons are labelled line by line.

Samples and lead time. Sample quantities are available for validation before a production order, and lead time is confirmable per order and per size once the specification is fixed.

8. FAQ

What is the difference between BSPP and BSPT, and can they be interchanged? BSPP (G thread, ISO 228-1) is a parallel thread where pressure tightness is not made on the threads, so the joint seals on a 60° cone seat or on a bonded washer against a flat face. BSPT (R, Rc, Rp thread, ISO 7-1) is a taper thread where pressure tightness is made on the threads and a sealant is required. They are not interchangeable: forcing a taper male into a parallel female port damages both threads and will not seal reliably.

What is the difference between a 60° cone seat and a bonded seal, and which should I choose? The 60° cone seat seals metal to metal where the male cone meets the matching cone in the port, with no extra sealing element. A bonded seal (Dowty-type washer) seals on a flat face and is compressed between the hex shoulder and the port face. Choose by the port: a cone port takes the cone seat, a flat-faced port takes the washer. This series supports both at both ends, so the same part number works with either port type.

How do I identify the correct 1BM size? Read the two threads off the ports rather than off the old part alone. Measure the BSPP thread and match it to the G column, and on the metric side measure the diameter and check the pitch with a thread gauge, then pick the row where that diameter and pitch meet the BSPP size you need. Watch the D suffix rows, because an M27X1.5 stud will not go into an M27X2 port.

What seal material should I select for my fluid and temperature? NBR covers general hydraulic oil service at approximately -30°C to +100°C. FKM (Viton-type) suits higher temperatures and many aggressive fluids at approximately -20°C to +200°C. EPDM is the choice for water-based fluids and steam at approximately -40°C to +120°C, and it is not compatible with mineral oil. Match the fluid first, then the temperature, and quote the fluid on the inquiry.

How is the working pressure of this adapter determined? Pressure is not fixed across the series: it follows the size, the body wall thickness, the sealing method at each end and the material, and it is confirmed per order by HENGHUA engineering with the quotation. In practice the connected hose or tube and the port often set the limit lower than the adapter, so state the system working pressure on the inquiry and the rating can be reviewed against it.

What is the minimum order quantity and can I get samples? Sample quantities can be supplied for validation, including with a nominated seal material and plating, so the joint can be checked on your own ports before a production commitment. Minimum order quantity is confirmed per order because it depends on the size mix and the material. Send the part numbers with the annual quantity and both figures come back with the quotation.

Does the D suffix change the part physically? Yes. The D marks the 1.5 mm pitch variant where the same nominal diameter is also catalogued at 2 mm pitch, so 1BM-12-27 is M27X2 and 1BM-12-27D is M27X1.5. The thread length and the hex may look the same, but the pitch is different and the two are not interchangeable in the port.

Can this series be supplied in stainless steel against a drawing? Yes. The series is available in carbon steel with trivalent chromium zinc plating, and in 304 or 316 stainless steel for corrosive and offshore service, including nominated plating and OEM marking on a drawing-based order. Send the drawing and the sizes and HENGHUA confirms the sample and the lead time.

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