Custom AN Fittings CNC Machining

Precision 37° flare seat machining

UNF threads gauged by dash size

5-axis machining for angled ports

Anodizing allowance planned in DFM

ISO 9001 IATF 16949 Rohs Certification

AN Fitting Challenges and How VMT Controls Them

Seat, thread and port problems tend to show up at the prototype stage, so these are the three points VMT controls most closely during AN fitting prototype machining and carries into production runs.

Microscope assisted deburring of machined parts

How Does VMT Control Sealing at the 37° Flare Seat?

The 37° flare seat seals by metal to metal contact, so small errors in angle, surface finish or alignment with the thread axis can become a leak path. VMT machines the seat and the thread in the same setup where the geometry allows, which helps keep them aligned, and checks the seat angle on an optical projector. Burrs at the seat edge can be removed by microscope deburring where required. This helps keep the seat within your drawing requirements before assembly.

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Anodized AN fittings with thread ring gauge

How Does VMT Manage Thread Fit After Anodizing?

Anodizing adds a thin layer that changes thread dimensions, so a thread that gauges well before finishing can bind afterward. VMT confirms the anodizing type and thickness, and whether thread dimensions apply before or after finishing, then sets the machined thread size to suit. Threads are masked where the drawing calls for it and checked with gauges after finishing. This can help your fittings meet the thread fit specified in your drawing.

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How Does VMT Control Port Angle and Position on Elbow and Tee Fittings?

On elbows and tees, extra clamping adds positioning risk for ports that must hold set angles to each other. VMT uses 5-axis machining to cut angled ports in fewer setups where the geometry allows, and checks port angle and position against the drawing on a CMM. This can help the finished ports match your drawing's angles and positions.

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Types of Custom AN Fittings VMT Machines to Your Drawings

VMT has machined all nine types of custom AN fittings below, and each has its own seat, thread and port details to get right, with the AN end set by dash size and every other feature made to your drawing.

AN Adapter Fittings

Joining lines with different connection standards means matching each interface's size and sealing style. VMT machines a custom AN to NPT adapter, or an ORB, BSPP or metric version, with the AN end on the 37° flare and the other end to its own standard.

AN Hose End Fittings

The hose end sets how a line connects and routes. VMT machines custom AN hose end fittings in swivel and push-lock designs for rubber and PTFE hoses, to match your hose and sleeve dimensions.

AN 45° and 90° Elbow Fittings

Tight engine bays and chassis routing leave little room for hose bends. VMT machines elbows at 45° and 90°, or at your specified angle, with port positions machined to the drawing.

AN Tee and Y Fittings

Branching a line adds ports whose angles and positions must match the layout. VMT machines tees and Y fittings with port angles, positions and sizes to your drawing, including mixed AN sizes.

AN Bulkhead Fittings

A line passing through a firewall or panel needs a fitting that mounts through it and locks in place. VMT machines custom AN bulkhead fittings to your panel thickness, mounting thread and port configuration on each side.

AN Weld-On Fittings

Tanks, coolers and fabricated housings need AN ports that weld in cleanly. VMT machines weld-on AN bases to your drawing, in a material that suits the part they are welded to, including the weld prep geometry.

AN Reducer and Expander Fittings

Mixed line sizes need a step between them. VMT machines reducers and expanders between specified AN sizes, or to nonstandard sizes from your drawing.

AN Cap and Plug Fittings

Unused ports and test points need closures that match the line. VMT machines AN caps and plugs to your drawing, in the material and port size your assembly calls for.

Manifold Blocks with AN Ports

Manifold blocks route several fluid paths through one machined body. VMT machines them with AN flare ports, while the internal passages, port layout and the other ports follow your drawing.

CNC Processes for Machining AN Fittings

Each AN fitting combines turned, milled and drilled features, so VMT matches the process to the feature being cut, from the flare seat and thread to the port layout.

CNC Turning

Turning forms the fitting body, the 37° flare cone and the external thread in one setup, keeping the seat aligned with the thread.

CNC Milling

Milling cuts the wrench flats, side ports and manifold faces on AN fittings and blocks, holding port spacing to your drawing.

5-Axis Machining

Angled elbow and tee ports are machined with five axes in one clamping, so port angles and positions follow the drawing with no second setup.

Swiss Turning

Swiss turning suits slender AN fittings and small dash sizes, since the guide bushing keeps the cut close to support.

Thread Machining

Threads are cut to the UNF dash size or your drawing, with external threads turned and internal ports tapped or milled, then checked with ring and plug gauges.

Deep Hole and Cross Drilling

Cross drilling and deep holes form the internal passages in manifold blocks, with port layout and intersections set by your drawing.

Custom CNC Machining AN Fittings Material Selection

In the field of parts machining, especially for the material selection of customized products, VMT provides a wide range of options to meet the needs and application scenarios of different customers. The following are common materials:

Available Materials
Aluminum	AL6061,Al6063,AL2024,AL6082,AL7075, ADC12, ect.
Stainless Steel	SS201,SS301,SS303,S31803,SS304,SS316, etc.
Steel	Low carbon steel, medium carbon steel, high carbon steel, alloy steel, etc.
Copper	C11000,C12000, C36000, etc
Brass	H59,H62,H65,H68, H80, etc
Iron	A36,45#,1213,12L14, etc
Plastic	ABS, PE, PC, POM, nylon, Peek, etc.
Other	Various composite materials.

Typical Surface Treatment of Parts Products

Before machining, our dedicated surface treatment engineers will select an appropriate and cost-effective surface treatment method based on your specific requirements to bring your ideas to life. We have provided surface treatment services for over 15,000 metal and plastic parts. Common surface treatments include:

Aluminum Parts	Anodizing, sandblasting anodizing, oil spraying, electroplating, wire drawing, polishing, etc.
Stainless Steel	PVD (vacuum coating), electroplating, passivation, etc.
Steel	Galvanized, black oxide, powder coating, etc.
Copper	Passivation, electroplating
Plastic	Painting, brushing (acrylic), printing, thermal transfer, etc.

Type II Anodizing

Hard Anodizing

Plating

Polishing

Powder Coating

Brushed

Electrophoresis

Blackened

Customized Logo

Bead Blasting

Passivation

Electropolishing

Design for Manufacturability Tips for CNC Machined AN Fittings

Most delays on AN fittings start in the drawing, so these six points cover the details to specify before machining starts, from flare wall thickness to thread relief and coating allowance.
These tips come from our engineers’ project experience. Every project is different, so not every point will apply to your design. For DFM advice specific to your part, send us your drawing and our engineers will review it with you.

Tube Wall Thickness for the 37° Flare▼

Flaring needs enough wall to form the seat without wrinkling or drifting out of center. Give the tube OD, wall thickness and material in the drawing, and VMT will set the flare allowance to match.

Thread Relief at the Shoulder▼

A thread cut right up to a shoulder concentrates stress at the root and can crack under vibration. A relief groove reduces that risk and gives the thread gauge room to finish cleanly.

Anodizing on Threads▼

Anodizing adds thickness to the thread, which can stop a mating part from threading in. Mark on the drawing whether threads are anodized or masked, so the fit is planned before machining.

Datum for Port Angles▼

Port angles on elbows and tees only hold if the drawing names a datum face. Without one, the quote, the setup and the inspection each pick a different reference, and parts come back for rework.

Cross-Hole Burrs Inside Manifolds▼

Where two drilled passages intersect, burrs form inside the flow path and are hard to reach. State on the drawing whether burrs are allowed, or whether the passage needs deburring or flushing after machining.

Galling on Stainless and Titanium Threads▼

Stainless and titanium threads tend to seize when mated with the same metal. Choose a material pairing or a coating for the mating thread, and note any thread lubricant requirement on the drawing.

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The Application of Custom CNC Machining AN Fittings

Custom CNC Machining AN fittings are widely used across many industries and by different types of users. Each system carries different fluids at different pressures in different packaging, so the fitting type changes with the application.

Motorsport：motorsport AN fittings include fuel pump feed fittings, oil cooler adapters and brake line fittings.
Automotive：automotive AN fittings include turbo oil feed fittings, fuel rail fittings and radiator hose adapters.
Industrial：industrial AN fittings include hydraulic manifold blocks, test bench bulkheads and pressure gauge adapters.
Marine：marine AN fittings include fuel tank fittings, engine cooling adapters and raw water elbows.
Aviation：aviation AN fittings include hydraulic line fittings, fuel line elbows and cap and plug sets.

Advantages of Our Custom CNC Machining AN Fittings Adapters

Looking for reliable AN fittings for high-performance or racing applications? Our custom CNC machining service delivers precision-made adapters that meet strict tolerance requirements, with machining accuracy up to 0.005 mm.

Our factory is equipped with 98 HAAS CNC machines and supports over 40 surface finishes, including anodizing, sandblasting, and polishing. We use high-strength 6061-T6 aluminum and other premium metals to ensure each fitting performs reliably under high pressure and temperature. All parts go through strict quality control, backed by ISO 9001 and IATF 16949 certifications, delivering a 99.98%+ yield rate.

Quality Inspection of Custom CNC Machining AN Fittings

Quality is our top priority. That is why we work only with trusted material suppliers and follow a 12-step inspection process, so every AN fitting meets your drawing. Each part is checked for size and surface finish at every stage, from raw material to final packaging.

Our quality team uses precision measuring tools to inspect critical dimensions, threads and sealing surfaces. Assemblies that carry fluid are leak tested before shipment. Inspection reports are created for each step and stored for two years for full traceability. Through this process, we maintain a 99.8% pass rate and deliver consistent CNC machined AN fittings you can rely on.

Advantages Gallery After-sales Service

Our Certificates

We are a custom CNC machining parts manufacturer with 15 years of experience and hold multiple certifications, including ISO 9001:2015, IATF 16949:2015, and SGS on-site inspection reports. We also offer NDA agreements to ensure confidentiality, a standard practice in our industry.

More About Our Company

VMT is a trusted CNC machining company with over 15 years of experience. We specialize in producing custom parts for a wide range of industries, offering comprehensive services from initial design and prototyping to full-scale production and advanced surface finishing. Equipped with state-of-the-art machinery and supported by a skilled team, we ensure every project is completed on schedule and meets the highest quality standards.

Based on customer requirements and the desired effects and materials, we provide a variety of surface treatments to enhance both the functionality and appearance of your parts. Our offerings include oxidation, sandblasting, polishing, electroplating, powder coating, baking paint, PVD coating, laser engraving, blackening, wire drawing, heat treatment, etching, and more.

6 people with 20 years of experience in dfm analysis engineering

2-Hour Quote

We provide quick and efficient quotations within just 2 hours. This ensures that your project can start immediately, helping you stay on schedule and make informed decisions early in the process.

DFM Analysis Report

Our DFM Analysis Report helps streamline your design process. This service saves time and avoids costly mistakes, allowing you to move forward with your project with confidence.

0.005 mm Tight Tolerance

At VMT, we achieve ultra-tight tolerances of up to ±0.005 mm, ensuring your parts fit and function with exceptional precision. Whether it’s for complex designs or demanding applications, we guarantee accuracy that meets the highest standards.

Lead Time as Fast as 3 Day

We understand the importance of time, which is why we offer lead times as fast as just 3 day. Our efficient processes and advanced equipment ensure that your orders are delivered quickly without compromising on quality.

40+ Materials and Finishes

VMT offers a wide range of over 40 materials and finishes, allowing us to meet diverse customer needs. From metals like aluminum and steel to specialized finishes like anodizing and powder coating, we provide tailored solutions for any project.

Industry Experience

With over 15 years of industry experience, VMT has built a reputation for excellence in CNC machining. Our broad expertise allows us to handle projects of any complexity, providing reliable solutions across a variety of industries.

Certificate

VMT is certified with industry-recognized standards like ISO 9001, ensuring our processes are constantly monitored and improved. With a yield rate of 98.8%, we are committed to delivering products that consistently meet or exceed customer expectations.

At VMT, we ensure the highest quality for all CNC machined parts. If your order doesn’t meet the specifications, we’ll reprocess the part or offer a refund. For any quality issues within one month, simply contact our team, and we’ll respond quickly to resolve the issue.

If issues arise, we’ll review the design and samples to find a solution. For problems after delivery, we’ll arrange a video call and send new samples if necessary. If the issue is our fault and cannot be fixed, we will process a refund or return promptly.

See What Our Customers Say About Us

Customer feedback is more powerful than any claim we can make. Our satisfied clients share how we’ve met their needs and delivered high-quality results. We take pride in the trust they place in us and are dedicated to continuing to deliver outstanding results for every project.

Bluetooth headset charger housing customer

August 2, 2024

The manufacturer is strongly recommended. In the past few years of cooperation we have ordered several machined products from aluminum and stainless steel. These products are manufactured in compliance with tolerance requirements and require product finish. Now I have ordered another one. The service is excellent and any questions can be answered and resolved in time.

AN Automotive Oil Cooling Joint Customer

May 13, 2021

The dimensions are all customized according to my drawings no tolerance issues and the parts are delivered on time. I am very satisfied with it.

Flashlight shell machining customers

April 6, 2021

I pay much attention to the surface treatment aspect of this product. I was a little worried about the cooperation at the beginning. I am very satisfied with the product now and hope to cooperate for a long time.

FAQ About AN Fittings

What is an AN-type Fitting?

AN fittings are precision-engineered connectors originally used in military applications. Made to strict aerospace standards, they use a 37° flare and are typically crafted from aluminum or stainless steel. They’re used in fuel, oil, and hydraulic systems for reliable, leak-proof performance.

Are AN and NPT the Same?

No, AN and NPT fittings are different. AN uses a 37° flare and straight threads, while NPT uses tapered threads that seal by thread deformation. Mixing them can cause leaks or failure.

What is the Difference Between AN and PTFE Fittings?

AN fittings refer to a type of thread and flare design, while PTFE fittings are used specifically with PTFE hoses. PTFE hoses often need special fittings that compress the hose liner without damaging it, but both types can sometimes work together with proper adapters.

What Fitting Mates with an Inverted Flare Thread?

An inverted flare fitting mates with a matching inverted flare nut and seat. It uses a 45° flare (not to be confused with the 37° AN flare) and is commonly used in brake and fuel lines in automotive applications.

What does the dash size mean?

The dash number is the tube outside diameter in sixteenths of an inch. For example, -6 is a 3/8 inch tube and -8 is a 1/2 inch tube, and each size has a fixed thread.

What is the difference between AN and JIC fittings?

AN and JIC fittings share the same 37° flare and dash sizes, but their threads differ: AN uses a tighter Class 3A/3B fit and JIC uses a looser Class 2A/2B fit, so the two are not interchangeable. Mixing them can cause loose threads and leaks, and the problem gets worse under pressure and vibration.

Choose AN when the drawing or system calls for aerospace, military or high-pressure motorsport specs, and choose JIC for hydraulic and heavy equipment. Always match the mating part.

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Customize Your CNC Machining AN Fittings Projects Now!

We specialize in CNC machining services. It integrates CNC machining, lathe processing, turning and milling combined processing, Swiss centering machining, 5-axis machining and prototyping. Contact us today for a free quote!