PRODUCT FEATURES
Negative Hex Bushing — Product Features
Water treatment, machinery piping, hydraulic & pneumatic equipment, light chemical, food equipment, pump & valve manifolds, confined space piping, instrument connection, threaded port size reduction.
Product Feature
Buyer Notes
Product Feature
EN 10204 3.1 material test certificate available for bulk orders. OEM marking is acceptable. Samples can be arranged for dimension & thread verification before mass production. Thread type and size combination need confirmation before order to prevent fitting mismatch on site.
OPERATING PRINCIPLE
How Negative Hex Bushing Works
1. Internal Hexagon Design: The hexagonal socket is recessed within the body, resulting in a compact structure with no exposed hex head—ideal for installations where space is limited.
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2. Male-to-Female Threading (Reducing)
The male-threaded end screws into a larger female-threaded port, while the female-threaded end (of a smaller size) connects to smaller-diameter male-threaded piping components.
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3. Fully Cast Construction
Features a dense internal structure free from pores or sand holes, offering high mechanical strength capable of withstanding high-pressure operating conditions.
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4. AISI 304 Stainless Steel
Provides excellent corrosion resistance; suitable for use with fresh water, mildly corrosive media, and outdoor installation environments.
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5. Precision-Machined Threads
Available with NPT, BSPT, or BSPP threads, ensuring a tight fit and reliable sealing.
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6. Pressure Rating
150LB; manufactured in accordance with MSS SP-83 and ASME B16.11 standards.
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7. Pickled and Passivated Surface
The surface is clean and features a protective anti-corrosion layer, ensuring a long service life.
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8. Wide Range of Specifications
Available in sizes from 3/4″ × 1/2″ to 2″ × 1/2″; custom marking/labeling options are supported.
ENGINEERING DATA
Technical Specifications
Technical data supplied for Negative Hex Bushing. Ratings and material combinations should be confirmed for the selected configuration.
| PARAMETER | SPECIFICATION |
|---|---|
| – Material | AISI 304 (ASTM A182 F304 / 1.4301) |
| – Type | Hexagon Reducing Bushing / Recessed Hex Reducing Bushing |
| – Thread Standard | NPT (ANSI B1.20.1) / BSPT / BSPP (ISO 7/1, DIN 2999) |
| – Pressure Rating | 150LB |
| – Manufacturing Standard | MSS SP-83, ASME B16.11 |
| – Surface Treatment | Pickling and Passivation |
| – Operating Temperature | -20°C to +200°C |
MECHANICAL DIMENSIONS
Dimensions & drawings.
Compare connection size with the corresponding overall length, bore and handle clearance dimensions from the supplied drawing.
Dimension chart
| SIZE | d | D | L |
|---|---|---|---|
| 3/4*1/2 | 24 | 30 | 39 |
| 1*1/2 | 30 | 38 | 39 |
| 1*3/4 | 30 | 38 | 41 |
| 1-1/4*1/2 | 38 | 46 | 42 |
| 1-1/4*3/4 | 38 | 46 | 43 |
| 1-1/4*1 | 38 | 46 | 46 |
| 11/2*1/2 | 45 | 52 | 41 |
| 1-1/2*3/4 | 45 | 52 | 44 |
| 1-1/2*1 | 45 | 52 | 47 |
| 1-1/2*1-1/4 | 45 | 52 | 45 |
| 2*1/2 | 57 | 65 | 47 |
| 2*3/4 | 57 | 65 | 48 |
| 2*1 | 57 | 65 | 51 |
| 2*1-1/4 | 57 | 65 | 53 |
| 2*1-1/2 | 57 | 65 | 53 |
Refer to the supplied dimension chart.
APPLICATIONS
Applications
Applicable media: the supplied document lists the following fluids. Actual compatibility depends on selected materials, concentration, temperature, pressure and the specific service conditions.
Application – Water Circulation
Cooling water, circulating water, drinking water and neutral purified water.
Application – Steam Piping
Clean, low-temperature saturated steam, subject to the product’s confirmed temperature and pressure limits.
Application – Compressed Air
Compressed air and nitrogen; verify compatibility for each system.
PURCHASING SUPPORT
Frequently Asked Questions
Find answers to common questions about sizing, materials, threaded connections and operating conditions.
What is Negative Hex Bushing?
It is a reducing threaded fitting with **external male thread (larger size) and internal female thread (smaller size)**, with hexagonal wrench flats. It screws into a larger female port and converts it down to a smaller female thread connection for pipe size transition.
Note: Negative Hex Bushing (Male × Female reducer) is different from reducer nipple (Female × Male) and cannot be mixed up.
What thread standards are available?
We support NPT (ASME B1.20.1), BSPT (Rc, EN10226), BSPP (G, ISO228-1).
Threads are not interchangeable. Please confirm thread standard + reducing size (e.g. 1″ × 1/2″) before order.
What stainless steel grades can you supply?
Standard grades:
– 304 / CF8 for water, air, general low-corrosion service
– 316 / 316L / CF8M for coastal, brine, chemical and chloride-containing media
Duplex, 321 and other special alloys available upon custom inquiry.
What standards and pressure rating?
Cast version follows ISO4144 / MSS SP-114, Class 150LB (PN20).
Forged bar stock version complies with ASME B16.11, available in 3000LB / 6000LB.
Pressure rating depends on material, wall thickness and forging/casting type.
Manufacturing process: casting or bar stock machined?
Standard stock items: lost wax investment casting.
High-pressure, high-precision or high-purity service: solid bar CNC machined, higher cost.
Manufacturing process: casting or bar stock machined?
Stock sizes: lost wax investment casting.
High-pressure / high-precision requirement: solid bar CNC machined, higher cost.
Surface finish options?
Standard: pickled matte finish. Optional: bright polish / satin brushed for food, beverage and sanitary pipeline systems.
Can you do laser marking?
Yes. We can mark size, grade, heat number, customer logo or brand on the hex flats.
Packaging for sea shipment?
Male threads are protected by plastic thread caps. Packed into export cartons, then loaded on fumigated wooden pallets with waterproof stretch film to avoid scratch and thread damage.
What is the lead time?
Typically, shipments are dispatched within 7–15 days of receiving the deposit, depending on the order quantity.
How is quality controlled?
Raw material inspection → CNC machining → Thread inspection → Hydrostatic testing → Visual inspection → Final dimensional verification before packaging.
Which Incoterms are available for overseas buyers?
We offer FOB (Free On Board) terms, with the shipment originating from a Chinese port. We will provide a commercial invoice, packing list, and bill of lading for import customs clearance.
Which Incoterms are available for buyers?
We offer FOB (Free On Board) or CIF (Cost, Insurance, and Freight) terms, with shipments originating from a Chinese port. We will provide a commercial invoice, packing list, and bill of lading for customs clearance.
What should be done if the threads are found to be defective or do not meet requirements upon arrival?
Please provide photos, videos, and inspection records. We will assess the root cause; depending on the contractual terms, solutions may include product replacement, a partial refund, or a reshipment.”
Negative Hex Bushing
304 Stainless Steel Forged/Cast Hexagon Reducing Bushing (Recessed Type), 3000 LB Pressure Rating; Available with NPT or BSP Thread Specifications.
This recessed-type hexagon reducing bushing is manufactured from 304 stainless steel via forging or casting. It features an external thread on the outside and a smaller-sized internal thread on the inside, designed for reducing pipe diameters. The recessed hexagonal design saves installation space, making it particularly well-suited for industrial piping systems with limited clearance. It offers excellent corrosion resistance. Material Test Certificates (MTC) are available upon request.
Type: Negative Hex Bushing
Material: 304/316L stainless steel
Nominal diameter: 1/2”–2” (D15–DN50)
Rated pressure: 150LB/3000LB
Connection type: Threaded connection (BSPT / BSPP / NPT)
