npt fittings

Stainless NPT Fittings Manufacturer – 316Ti/316L/304 NPT Pipe Fittings

QC Hydraulics is a China trusted manufacturer with over 25 years of experience supplying high-quality stainless NPT fittings. Made from 316Ti, 316L and 304 stainless steel, our fittings are designed for reliable performance in hydraulic, industrial, marine, and food-grade systems. We support bulk orders, OEM production, and global distribution.

Explore Our Full Range of NPT Fittings & Adapters

QC Hydraulics specializes in the production of stainless steel NPT fittings and adapters, engineered in accordance with ANSI/ASME B1.20.1 (NPT) and B1.20.3 (NPTF) standards. Each fitting features a precision-machined 60° thread angle that ensures a secure, metal-to-metal seal — ideal for high-pressure hydraulic and industrial systems.

NPT fittings are widely used across North America to create leak-tight, pressure-resistant connections in piping systems. Their tapered thread design provides reliable sealing for a variety of applications, including oil & gas, fluid transfer, and process piping.

✔ Wide size range: 1/8″ to 2″

✔ Made of 316Ti / 316L / 304 stainless steel

✔ Leak-free and pressure-tested up to 6,000 PSI

✔ Thread types: JIC, NPT/NPTF, ORB, ORFS, BSPP, metric

✔ Standard: ANSI/ASME B1.20.1(NPT) & ANSI/ASME B1.20.3(NPTF)

✔ Fitting types: adapter, 45° and 90° elbows, tee, cross, plug, caps & plugs, bulkhead

NPT Fittings Thread Sizes & Dimensions

NPT dash size is a shorthand used to represent the nominal size of an NPT fitting, based on 1/16-inch increments.

For example: Dash -04 = 4 × 1/16 = 1/4″ NPT, Dash -08 = 8 × 1/16 = 1/2″ NPT

Each dash size corresponds to specific thread dimensions: Tapered thread with a 60° angle

Threads per Inch (TPI) vary by size (e.g., 1/2″ NPT = 14 TPI)

Major OD is larger than the nominal size (e.g., 1/2″ NPT ≈ 0.840″ OD)

Inch Size Dash Size Threads per Inch Male Thread O.D. (in) Male Thread O.D. Female Thread O.D. (in) Female Thread O.D.
1/8 -2 27 13/32 0.41 3/8 0.38
1/4 -4 18 17/32 0.54 1/2 0.49
3/8 -6 18 11/16 0.68 5/8 0.63
1/2 -8 14 27/32 0.84 25/32 0.77
3/4 -12 14 1 1/16 1.05 1 0.98
1 -16 11 1/2 1 5/16 1.32 1 1/4 1.24
1 1/4 -20 11 1/2 1 21/32 1.66 1 19/32 1.58
1 1/2 -24 11 1/2 1 29/32 1.90 1 13/16 1.82
2 -32 11 1/2 2 3/8 2.38 2 5/16 2.30

NPT/NPTF Fittings Pressure Ratings

Working pressure ratings are designed to meet a minimum burst pressure ratio of 4:1.

Nom SAE
Dash Size		 Nom Inch
Pipe O.D.		 Thread Size Fittings With NPTF
Pipe Threads		 Adapter Unions
Dryseal Pipe Thread
(NPTF1)		 Straight Pipe Thread
(NPSM2)		 MPa psi MPa psi
-2 1/8 1/8-27 1/8-27 34.5 5000 34.5 5000
-4 1/4 1/4-18 1/4-18 27.5 4000 34.5 5000
-6 3/8 3/8-18 3/8-18 21 3000 27.6 4000
-8 1/2 1/2-14 1/2-14 21 3000 24.1 3500
-12 3/4 3/4-14 3/4-14 17 2500 15.5 2250
-16 1 1-11-1/2 1-11-1/2 14 2000 13.8 2000
-20 1 1/4 1-1/4-11-1/2 1-1/4-11-1/2 8 1150 11.2 1625
-24 1 1/2 1-1/2-11-1/2 1-1/2-11-1/2 7 1000 8.6 1250
-32 2 2-11-1/2 2-11-1/2 7 1000 7.8 1125

1 Dryseal American Standard Taper Pipe Thread
2 American Standard Straight Pipe Thread for Mechanical Joints

NPT Fittings Assembly Torque

Pipe Size Adapter Unions Pipe Tapered Pipe
T.F.F.T.2
(Turns)
Ft. Lbs. Max. Nm Max. Ft. Lbs. Max. Nm Max.
1/8 13 18 12 16 3/4 – 1 3/4
1/4 20 27 25 34 3/4 – 1 3/4
3/8 25 34 40 54 3/4 – 1 3/4
1/2 47 64 54 73 1/2 – 1 1/2
3/4 84 114 78 106 1/2 – 1 1/2
1 129 175 112 152 1/2 – 1 1/2
1-1/4 152 206 154 209 1/2 – 1 1/2
1-1/2 152 206 211 286 1/2 – 1 1/2
2 300 407 300 407 1/2 – 1 1/2

1 Lubricated assembly.
2 Tapered pipe connections use turns from finger tight. Turn past minimum for alignment of shape fittings.

Assembly For NPT Thread Fittings

Method A. Installation Torque

1. Inspect components for damage or contamination.

2. Lubricate or apply compatible sealant to male pipe thread.

3. Screw fitting into port until hand tight. For shape fittings, take note of the intended alignment of the mating connectors.

4. For straight fittings, tighten to recommended torque listed in the following table. For shape fittings, approximately 1/2 turns should be made and then torque to the desired orientation without exceeding maximum recommended torque.

Method B. Turns From Finger Tight (T.F.F.T.)
Note: Due to the variety of factors which affect the turns method, the values indicated are approximate and should be used only for initial installation, by experienced installation personnel.

1. Inspect components for damage or contamination.
2. Lubricate or apply compatible sealant to male pipe thread.
3. Screw fitting into port and lightly wrench to seat threads.
4. Mark fitting and adjacent surface to indicate initial seating position.
5. For straight fittings, tighten using mean to maximum recommended T.F.F.T. listed in Table I.
6. For shape fittings, tighten to minimum T.F.F.T., and turn past to desired orientation.
7. Mark final tightening position by extending the existing mark from the fitting to the adjacent surface.

Technical Support

QC Hydraulics has the capability to engineer, design and manufacture from a concept to the real products.

Please feel free to contact us if you have any inquiries

QC Hydraulics, Your Premier Stainless Steel Hydraulic Fittings And Adapters manufacturer

QC Hydraulics is a leading manufacturer of stainless steel hydraulic hose fittings, hydraulic adapters, tube fittings and PTFE hose assembly for over 20 years. Our outstanding team, state of the art technology, strict quality control, strong production capacity as well as professional service, enable us enjoying a great reputation in domestic and overseas.

Our products are widely recognized by those global hydraulic & industrial wholesalers/distributors and OEMs in the fields of hydraulic, pneumatic, oil & gas, chemical, marine and shipbuilding etc. Besides, we are also doing OEM service for several of worldwide big brand manufacturers of hydraulic fittings, which greatly reduce their production costs, and help them win more market share.

Now QC Hydraulics become more and more popular in high quality market overseas. We always meet even exceed customer’s expectations. QC Hydraulics is a reliable and trusted supplier of wholesalers, distributors and brand manufacturers of hose and fittings.

  • State of The Art Facilities

  • Over 20 years’ Manufacturing Experience

  • Highly strict Quality Control & Inspection

  • Annual production capacity Over 4.5 million of fittings

Why Choose Us

State of The Art Facilities

We utilize state-of-the-art facilities and equipment to produce industry leading, quality stainless steel hydraulic fittings. Each facility supervisor has over 10 years of experience in the industry. Manufacturing, sales & technical support, warehouse, shipping, and quality control-have specific objectives that contribute to our overall goal of 100% customer’s satisfaction.

Zero Quality Issues

When you buy QC Hydraulics’ products, you are buying precision and reliability.In the hydraulic industry, where extreme pressures prevail, precision and accuracy are paramount. Our Quality Control Department follows strict Quality Assurance Program procedures that make certain our products meet your quality requirements. Besides, 3.1 material certificate available for each shipment to ensure you receive 100% right materials from us.

100% On-Time Delivery

With QC Hydraulics, you’ll have one less thing to worry about. We have maintained a 99.99% on-time delivery rate for 3 years in a row. That kind of consistency doesn’t just happen, we make it happen. Besides, we have the commonly used raw materials and accessories in stock that enable us make a very quick delivery time for the urgent orders.

Professional Service

As a professional manufacturer, our engineering department can provide technical service. Like new products designing, CAD drawings and technical advice. Our overseas sales department are 100% well trained with strong industry & product knowledge and service awareness, who can make a quick response within 24 hours to greatly improve the communication efficiency.

Frequently Asked Questions

We manufacture a wide range of stainless steel hydraulic adapters, including:

JIC, ORFS, NPT, NPTF, BSP, BSPT, SAE, and Metric thread types

Straight, 45° & 90° elbows, tees, crosses, reducers, and plugs

Interchangeable with Parker and Eaton standard adapters

Our adapters are designed to meet SAE, ISO, DIN, and JIS standards.

Yes, we provide standard bulk packaging as well as custom packaging options based on customer requirements. Our standard packaging includes:

Plastic caps and plugs to protect threads and sealing surfaces

Individual polybags for small-sized adapters

Heavy-duty cartons with reinforced packing for safe transportation

For distributors and wholesalers, we can also provide private labeling and custom branding.

We manufacture adapters using high-quality stainless steel:

AISI 304 (1.4301)

AISI 316L (1.4404)

AISI 316Ti (1.4571)

These materials provide superior corrosion resistance, making them ideal for high-pressure and harsh environments

Yes, we do both hydrostatic pressure and nitrogen gas pressure test. Testing reports are avaliable.

Yes, we offer custom manufacturing services for hydraulic adapters based on customer drawings, specifications, or samples. Our engineering team can assist with design modifications, thread compatibility, and performance optimization to meet specific application requirements.

Our standard MOQ is 200 pieces per item, but for larger sizes (above 1 inch), we can accept 100 or even 50 pieces. We are flexible with initial orders to help customers test our quality

Yes, we provide EN 10204 3.1 material certificates for all shipments. Our stainless steel raw materials meet ASTM A276 and ASTM A182 standards, ensuring compliance with industry regulations.

Stainless Steel Only: Unlike many suppliers who offer both carbon steel and stainless steel, we focus exclusively on stainless steel, ensuring better precision and quality.

Advanced Manufacturing: We use high-precision CNC machining and strict quality control measures.

Guaranteed Quality: 100% pressure-tested, dimensionally accurate, and ISO 9001 certified.

On-Time Delivery: Reliable lead times and stock management ensure prompt shipments.

Interchangeability: Compatible with leading global brands like Parker and Eaton.

Send us a message if you have any questions or request a quote.

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