Fuel Fitting

Buell Automatics specializes in precision CNC machining and multi-spindle screw machining services. Our company has been producing precision products for over 50 years. We provide fast and cost-effective manufacturing solutions across multiple industries and applications.

Machined fittings and connectors are one of our most popular services. Our CNC machining and multi-spindle screw machining experience facilitates the fabrication of high-quality fittings and connectors from a variety of material grades. The fittings and connectors are used in applications such as:

  • Fuel/Water/Steam/Chemicals/Fluids
  • Valves/Hydraulics/Solenoids/Pneumatics/Pumps
  • High Pressure/Low Pressure
  • Quick Disconnect/Adaptor-Port/Pipe/Compression/Flanged/Welded/Brazed/Flared

Types of Fittings and Connectors

There are multiple types fittings and connectors.

Buell Automatics can support many of the following types of fittings and connectors:

1. Quick Disconnect Fittings

Also called push fittings, are used in many applications such as air, pneumatics, plumbing, heating, fire suppression, and everywhere in between. Such fittings offer the benefits of significant time savings over older devices for connecting tubes and hoses, and require little skill for their usage. Users themselves can equip tubing with thread-less push fittings specially made with teeth that are forced deeper into the tubing when opposing force is applied to them, preventing their separation from the tubing.

2. Adapter/Port Fittings

Adapter fittings—also called standard or union fittings—use straight threads and an O-ring to seal against leakage, which enables highly reliable installation. These fittings connect fuel lines to pumps, regulators, and filters and resist damage from extreme heat and contact with fuel and other chemicals. These are typically made from Stainless Steel in accordance with our customers specifications.

2. Pipe Fittings

Pipe and Port fittings connect fluid lines to pump ports and regulators for example. The Pipe fitting has a combination of tapered threads to fit into female ports, while the other end can be has straight threads, while Port threads have straight threads on both ends. While tapered threads seal the pipes and lines, these threads present a slightly higher leak risk even when sealed with Teflon tape.

 4. Compression Fittings

Used in plumbing and electrical conduit systems to tubes or thin-walled pipes together. The fittings will be made of one or more compatible materials appropriate for the connection. Compression fittings typically have ferrules in them, and are used for hot and cold water faucets as well as toilet stop valves. These connections are usually used in confined spaces where soldering is difficult.

5. Flanged Connectors

Bolted flange connectors are suitable for most pressures now in use. The flanges are attached to the piping by welding, brazing, or tapered threads, or by rolling and bending into recesses. Those illustrated are the most common types of flange joints used. The same types of standard fitting shapes-tee, cross, elbow, and so forth-are manufactured for flange joints. Suitable gasket material must be used between the flanges.

6. Welded Connectors

Welded joints connect the subassemblies of some fluid power systems, especially in high-pressure systems that use pipe for fluid lines. The welding is done according to standard specifications that define the materials and techniques.

7. Brazed Connectors

Silver-brazed connectors are commonly used for joining nonferrous piping in the pressure and temperature range where their use is practical. Use of this type of connector is limited to installations in which the piping temperature will not exceed 425″F and the pressure in cold lines will not exceed 3,000 psi. Heating the joint with an oxyacetylene torch melts the alloy. This causes the alloy insert to melt and fill the few thousandths of an inch of annular space between the pipe and fitting.

8. Flared Connectors

Flared connectors are commonly used in fluid power systems containing lines made of tubing. These connectors provide safe, strong, dependable connections without the need for threading, welding, or soldering the tubing. The connector consists of a fit­ting, a sleeve, and a nut.

Straight Threads vs. Tapered (Pipe) Threads

The threads in straight-threaded fittings run parallel to each other. The shaft of the fitting also stays straight until the end without reducing in diameter or tapering. Fittings with straight threads employ O-rings to create a complete seal. Adapter and port fittings use only straight threads.

In the United States, straight threads must meet American National Standard Straight Pipe Thread (NPS) or American Standard Straight Coupling Pipe Thread (NPSC) standards, depending on the type of pipe and application.

Conversely, tapered threads run along a 2-degree angle. The shaft often tapers to wedge into the fitted surface’s opening. The tension between the shaft, threads, and opposing surface provide a nearly complete seal. Adding Teflon tape makes the seal stronger against potential leaks. Pipe fittings typically only have one end with tapered threads.

In the United States, tapered threads follow American National Standard Taper Pipe Thread standards (NPT).

AN Thread Sizing

Army-Navy (AN) sizes are a standard framework for measuring and detailing straight thread sizes. Each number in the scale denotes the size of the outside diameter of a shaft or tube in increments of 1/16 of an inch. Every AN size has a standard thread size. For example, a size 2 tube, according to AN sizing, has a 1/8-inch outside diameter and thread sizes of 5/16-24 SAE. AN sizing continues to size 32, or a 2-inch tube with 2-1/2-12 SAE threads.

NPT sizing, on the other hand, is a scale for tapered threads.

Case Study: Stainless Steel Automotive Fuel Emissions Fittings

Since 1966, Buell Automatics has been helping companies meet all kinds of small part needs, assisting clients throughout every step of the manufacturing process — from initial design to finished product. To better illustrate how we work with customers to craft high-quality, customized solutions, we’ve outlined a case study below.

The Problem

A company recently approached us about the assembly of their automotive fuel emissions fittings; before contacting us, they had been procuring them from another manufacturer, who used cold drawn plated steels to create the parts.

The customer was new to Buell and looking for a change; the cold drawn plated steel fittings were resulting in long lead times and inconsistent, unreliable quality, thereby putting larger systems in danger. So, the company requested that we use stainless steel, rather than cold drawn plated steels, in the assembly of these key automotive components.

The Solution

Typically, stainless steel is a difficult material to work with, but our expert team was able to create a reliable, high-quality solution working with our Davenport five-spindle screw machine, which was enhanced with the use of our proprietary coolant through drilling. This coolant allows us to machine more complex parts at faster turnaround times and lower costs.

Our expert manufacturing engineers and Davenport machine setup and production personnel completed several processes to ensure the highest-quality, most reliable results possible — turning, deep hole drilling, milling, facing, and cutoff. Though our team initially had difficulty getting the slot (leak path) in the fitting, they quickly found success after switching from broaching to milling. After completion, we did a comprehensive visual inspection to ensure optimal quality.

The Result

Ultimately, through the use of our Davenport machining, in-house coolant, and deep hole drilling capabilities, we were able to reduce the production time needed to manufacture the fitting while also providing our client with significant cost savings.

The customer was very pleased with the final stainless automotive fuel emissions fitting and has since partnered with us for additional projects. In fact, this client recently submitted a request to manufacture a new fuel emissions fitting from 303 stainless steel. They were also able to sell the stainless steel fuel emissions fitting to their own customers, generating new business for their company as well as our own.

Precision Fittings with Buell Automatics

It’s essential to choose the right adapter, pipe, and port fittings for high-end fuel line systems and transportation equipment. Straight and tapered threads require different sealing methods. Buell Automatics can fabricate high-quality fittings with both straight and tapered threads to meet your company’s needs. Contact us today to learn more or receive a quote for your order.

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