What is the definition of "SAE straight-thread O-ring boss"?
A reusable fitting that is sealed by an O-ring located between the termination of a straight OD thread and the wrench flats used to tighten the fitting inside a component. Also called a straight thread O-ring fitting.

Learn more about SAE straight-thread O-ring boss in the class Fittings for Fluid Systems 135 below.


Hydraulics and Pneumatics Training


Class Information
Tooling U-SME classes are offered at the beginner, intermediate, and advanced levels. The typical class consists of 12 to 25 lessons and will take approximately one hour to complete.
Class Name:Fittings for Fluid Systems 135
Description:This class provides an overview of fittings for fluid power systems, including pipe fittings, tube fittings, hose fittings, and the seals that make them work.
Prerequisites: 570130
Difficulty:Beginner
Number of Lessons:17
Language:English, Spanish
 
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Class Outline
  • Objectives
  • What Is a Fitting?
  • Positive and Nonpositive Seals
  • Dynamic and Static Seals
  • Pipe Fittings
  • Pipe Fittings for Direction Changes
  • Pipe Fittings for Extension and Termination
  • Flare-type Tube Fittings
  • Flareless Fittings
  • O-rings
  • Straight Thread and Face Seal O-Ring Fittings
  • Split-Flange O-Ring Fittings
  • Hose Fittings
  • Quick Disconnect and Quick Connect Fittings
  • Installation
  • Fittings Maintenance
  • Summary
  
Class Objectives
  • Describe fittings.
  • Distinguish between nonpositive and positive seals.
  • Distinguish between dynamic and static seals.
  • Describe pipe fittings.
  • Identify pipe fittings used for direction changes.
  • Identify pipe fittings used for extension and termination.
  • Describe flare-type tube fittings.
  • Label the main components of a flareless fitting.
  • Describe an O-ring.
  • Identify a straight-thread O-ring fitting.
  • Describe a split-flange O-ring fitting.
  • Describe hose fittings.
  • Describe quick disconnect and quick connect fittings.
  • Distinguish between proper and improper fitting installation.
  • Describe proper routine maintenance for fittings.

Class Vocabulary

Vocabulary TermDefinition
45° elbow fitting A hose fitting with female threads that runs off the end of the hose at 45° angle.
45° male elbow A steel tube fitting that joins two tubes at a 45° angle.
90° elbow fitting A hose fitting with female threads that runs off the end of the hose at a 90° angle.
adapter A pipe fitting that extends a run by joining two pipes of different types.
adjustable straight thread O-ring fitting A reusable fitting that is sealed by an O-ring located between the termination of a straight OD thread and a washer and locknut. The adjustable straight thread O-ring fitting can be tightened and fixed in any orientation.
barb An angled cylindrical feature on the OD of a fitting that grabs and holds the ID of a hose. Barbs are designed so that hose is easily mounted over the fitting, but is difficult to remove.
barbed fitting A fluid power fitting used with hose. A barbed fitting is characterized by the presence of angled barbs that grab and hold on the ID of a hose.
bell reducer A pipe fitting that extends a run by joining two pipes of different diameter. Often called a reducing coupling.
bite-type fitting A fitting with a sharpened ferrule that "bites" the tube when compressed. The bite of the ferrule provides the seal.
cap A pipe fitting that terminates a run by closing an end. A cap has female threads.
captive nut A nut that is affixed to a fitting. Because a captive nut is part of a fitting, the captive nut is a means to rotate the entire fitting.
clamp A mechanical device used to compress the flange against the O-ring in a split-flange O-ring fitting.
compression The force applied when two mating, threaded fitting components are tightened together. Compression is the primary force behind many of the fluid power seals.
compression fitting A type of tube fitting that is sealed by pressure caused by the interaction of threaded portions of the fitting.
crest The high point of a thread.
crimping The process of mechanically attaching a permanent fitting to the end of a hose. Crimping involves squeezing the metal fitting until it is bound to the hose.
cross A pipe fitting that joins one pipe run to another that runs perpendicular and through the main run.
deburr To remove sharp projections left by the cutting tool after a cutting operation.
double shutoff quick disconnect fitting A quick disconnect fitting with one valve located in the stud connected to the hose and another valve located inside the fitting component that attaches closest to the air supply.
dryseal A sealing condition caused by the crest of one thread contacting the root of another thread. Dryseals do not allow fluid to leak from a fluid system.
dynamic seal A seal that is made between two objects that move relative to one another during operation.
elbow A pipe fitting that changes the direction of a pipe run. Ells are available in 22.5°, 45°, 60°, and 90° and have female threads on both ends. Elbows are also called ells.
ell A pipe fitting that changes the direction of a pipe run. Ells are available in 22.5°, 45°, 60°, and 90° angles and have female threads on both ends. Ells are also called elbows.
external leakage The unintentional movement of fluid from a system into the environment.
face seal O-ring A means of attaching and sealing the other end of the flare-type or flareless fitting body to a component. The face seal O-ring acts much like a non-adjustable straight thread O-ring fitting.
female thread A type of thread that appears on the inner diameter of a cylindrical part or hole.
ferrule A sleeve that provides a seal when compressed between two mating fitting components.
ferrule The sleeve-like portion of a flareless fitting that provides a seal by being compressed.
ferrule compression fitting A type of two-piece compression fitting that forces a metal sleeve, or ferrule, against the tube as the fitting is tightened.
fitting A fluid component that connects, redirects, extends, or terminates the run of a fluid conductor.
flange A short cylindrical component used to seal and reinforce the connection between a fitting and a conductor. A flange fits around the conductor and is held in place by clamps.
flank The side of a thread between the root and crest.
flare fitting A type of tube fitting that is connected to a flared end of a tube.
flareless fitting A fitting that achieves a seal through the compression of mating parts and a ferrule on the unflared end of a tube or hose.
flare-type fitting A fitting that achieves a seal through the compression of mating parts on the flared end of a tube.
flat-face O-ring A means of attaching and sealing the other end of the flare-type or flareless fitting body to a component. The flat-face O-ring acts much like a non-adjustable straight thread O-ring fitting.
hose clamp A circular clamp that fits around the OD of a hose where it meets the barbed fitting. A hose clamp provides pressure so that the hose does not slip off the barbed fitting.
hose fitting A type of fitting used to connect a hose to another fluid component.
inner diameter The interior surface of a cylindrical part or hole.
interference The primary cause of pipe seals. Interference is caused by the interaction of inner diameter and outer diameter threads when tightened together.
internal leakage The unintentional movement of fluid from one component to another.
land The portion of a flareless fitting into which the end of a tube is placed.
leakage The movement of fluid either out of a fluid system or from one fluid component to another. Leakage causes a loss of effiency and often leads to system failure.
locknut A component of an adjustable straight thread O-ring fitting that tightens an O-ring between a washer and the flat surface of a fluid component.
lubrication The application of a substance to reduce friction between two surfaces in relative motion. Oil and grease are commonly used for lubrication.
male thread A type of thread that appears on the outer diameter of a cylindrical part or round feature.
manifold A block of metal with multiple integrated channels designed to conduct fluid in confined spaces.
metal-to-metal fitting A fitting that achieves a seal through contact between two metal surfaces.
nipple A small section of pipe of varying length used to connect fluid components.
non-adjustable straight thread O-ring fitting A reusable fitting that is sealed by an O-ring located between the termination of a straight OD thread and the wrench flats used to tighten the fitting inside a component. This type is non-adjustable because it does not point in any particular direction.
nonpositive seal A seal that allows a small amount of fluid to pass through.
nut The portion of a flareless fitting that is tightened to provide compression on the ferrule of a flareless fitting.
O-ring A flexible, rubber-like ring that is used to create a mechanical seal. O-rings are usually located in a groove and compressed between two or more fitting components.
O-ring compression fitting A type of two-piece tube fitting that, when tightened, squeezes an O-ring and forms a seal.
O-ring fitting Any fluid power fitting that uses an O-ring as the primary sealing mechanism.
outer diameter The exterior surface of a cylindrical or round feature.
permanent fitting A hose fitting that is attached to the hose on a continuing basis.
permanent hose fitting A fitting that is permanently attached to a hose. When the hose or fitting fails, both must be discarded.
pipe fitting A type of fitting used to connect, redirect, extend, or terminate a pipe run. Pipe fittings come in a variety of shapes and are often named for the letters they resemble.
plug A pipe fitting that terminates a run by closing an end. A plug has male threads.
positive seal A seal that does not allow any amount of fluid to pass through.
preventive maintenance Maintenance performed while a component is in working order to keep it from breaking down. Preventive maintenance includes lubricating, tightening, and replacing worn parts.
push-lock reusable fitting A reusable fitting that is forced onto the end of a hose and locked into place.
quick connect fitting A fitting that is designed to attach to a line quickly and efficiently. A quick connect fitting is often a one-piece fitting that is forced onto the end of a hose and locked into place.
quick disconnect fitting A fitting designed for use with components that are moved often and for avoiding disrupting system air pressure or compromising safety.
quick-connect fitting A hose fitting that can be connected and disconnected with ease.
reducing bushing A pipe fitting with male and female threads that extends a run by joining two pipes of different diameter.
reducing coupling A pipe fitting that extends a run by joining two pipes of different diameter. Often called a bell reducer.
reusable fitting A hose fitting that may be used again once the hose wears out and is replaced.
reusable hose fitting A fitting that is not permanently attached to a hose. When the hose fails, the fitting may be mounted on a new hose.
root The bottom of a thread valley.
rotary seal A dynamic seal achieved between a stationary cylinder and a rotating piston or shaft located inside the cylinder.
rotary union A fitting component designed to provide a dynamic seal while rotating continuously at high speeds.
run-to-failure A maintenance policy that allows a component to run until it breaks down, at which point reactive maintenance may be performed.
SAE straight-thread O-ring boss A reusable fitting that is sealed by an O-ring located between the termination of a straight OD thread and the wrench flats used to tighten the fitting inside a component. Also called a straight thread O-ring fitting.
seal An intentional obstruction designed to keep fluids inside a fluid power system.
single shutoff quick disconnect A quick disconnect fitting with a valve located inside the fitting component that attaches closest to the air supply.
sleeve compression fitting A type of two-piece compression fitting that forces the tube into a metal sleeve and creates a seal by partially distorting the end of the tube.
spiral clearance The presence of space between the root of one thread and the crest of another along the entire length of the thread. Spiral clearance allows fluid to leak from a fluid system.
split-flange O-ring fitting An O-ring fitting used for large OD tubing. To form a seal, a flange is tightened over an O-ring with clamps.
static seal A seal that is made between two stable and immovable components.
straight coupling A pipe fitting that extends a run by joining two identical pipes end on end.
straight fitting A hose fitting with male threads that runs straight off the end of the hose.
straight thread O-ring connector A type of tube fitting with straight, untapered male threads used to connect two tubes. An O-ring is used to form the seal.
straight thread O-ring fitting A reusable fitting that is sealed by an O-ring located between the termination of a straight OD thread and the wrench flats used to tighten the fitting into a component. Also called an SAE straight-thread O-ring boss.
straight through quick disconnect fitting A quick disconnect fitting with no valves. Straight through disconnect fittings cannot be added or removed without first shutting off the air supply.
street ell An ell pipe fitting with female threads on one end and male threads on the other.
stud The component of a quick disconnect fitting that attaches to a hose.
swivel A fitting component designed to provide a dynamic seal while rotating at low speeds, often at less than 360° of rotation.
tapered Gradually decreasing in size from one end of the object to the other.
tee A pipe fitting that joins one pipe run to another that runs in one direction perpendicular to the main run.
tee wye A pipe fitting that joins one pipe run to another that initally runs in one direction at 45° and eventually tapers to 90 degrees.
torque The force exerted in rotation.
union A fitting that extends a run by joining two conductors without turning the conductors to tighten the seal.
union elbow A steel tube fitting that joins two tubes at right angles, or 90 degrees.
union tee A steel tube fitting that joins three tubes. The union tee has the shape of the letter "T."
upstream In a direction toward the source of power in a fluid system. Upstream in a pneumatic system is in the direction from which the air is coming.
washer A component of an adjustable straight thread O-ring fitting that is squeezed by a locknut against the O-ring.
wrench flat One of several leveled areas around the outer diameter of a component that allow it to be turned by a tool such as a wrench.
wye A pipe fitting that joins one pipe run to another that runs in one direction at 45° to the main run.