USES AND APPLICATIONS OF LEFT-HANDED THREADS

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LEFT-HANDED AND RIGHT-HANDED FASTENER THREADS: USES AND COMPARISON
Fasteners are the nuts, boltsscrews, and other small components that keep machinery and components together in working order. Many fasteners work through the effective use of threads (left-hand thread and right-hand thread), which allow nuts and bolts to screw together effectively.

But how do threads work? The direction in which workers screw and unscrew fasteners has a lot to do with the applications in which they appear. Additionally, many different types of threads exist to optimize different ways to fasten objects. 

COMMON USES AND APPLICATIONS OF FASTENER THREADS
Screw threads help with many different applications, such as:

  • Fastening: Screw threads appear on traditional fasteners such as nuts, bolts, and screws, and they also help connect threaded pipes, hoses, caps, and fixtures
  • Gear reduction: Screw threads help with gear reduction by using worm drives
  • Linear object movement: Fastener threads can be used to convert rotary motion to linear motion

 

UNDERSTANDING RIGHT-HANDED VS. LEFT-HANDED THREADS
THREAD TERMINOLOGY AND DIFFERENT TYPES
Threads are continuous helical ridges on cylindrical fasteners. For parts such as screws, the ridges will be on the exterior, and parts like nuts have ridges inside of their cylindrical bodies.

There are a number of common terms to describe different aspects of threads, which we define below:

  • External threads: Threads that wind around the exterior of a fastener’s shaft
  • Internal thread: Threads that run along the inside of a fastener
  • Axis: Longitudinal lines used to measure the length of the fastener
  • Pitch: The distance between a point on one thread to a point on another thread
  • Major diameter: The largest internal or external thread diameter
  • Minor diameter: The smallest internal or external thread diameter

 

FASTENER THREADS: WHAT IS A SCREW THREAD?
Screw threads are sloped helices that spiral down the cylindrical surface of parts like screws and bolts. They’re responsible for converting energy between rotational and linear movement and force. Fasteners with compatible threads can provide tight seals for a wide variety of equipment.

SCREW HANDEDNESS: LEFT-HAND THREAD AND RIGHT-HAND THREAD
Screw handedness refers to the direction that a screw’s thread wraps around its shaft. Right-handed threads run clockwise, and left-handed threads run counterclockwise. The origin of a thread’s handedness is rooted in human physiology: Screws with different handedness are ergonomic for people depending on their dominant hands.

Most screws today use right-handed threads, and it’s rare to find a left-handed screw used in any application that doesn’t specifically call for it. However, there are some applications that specifically call for the use of left-handed fasteners.

USES AND APPLICATIONS OF LEFT-HANDED THREADS
Left-handed threads are also known as reverse threads. These threads are used in specialized applications in which the application of pressure would force a right-handed screw or bolt to come loose.

Some applications that benefit from the use of left-handed fasteners include:

  • Automotive: Some tires’ bolts are reverse threaded to keep torque from loosening them
  • Heating and plumbing: Pipes are often fitted with both right- and left-handed threads to provide an extra layer of defense from leakage
  • Safety: Gas-supply valves use left-handed threads to differentiate them from the valves that control oxygen

 

QUALITY FASTENING SOLUTIONS BY NATIONAL BOLT
National Bolt builds custom nonstandard fasteners, large-diameter products, and more, and we pride ourselves on our quick turnaround and delivery times.

 

Continued supply chain chaos Made in USA affordable / logistical option 
National Bolt & Nut's large inventory of standard fasteners can prevent line down situations. NBN offers quick turnarounds on non-standard fasteners.

Watch>>>Custom Bolts and Fasteners | National Bolt & Nut Corporation

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CUSTOM BOLTS AND FASTENERS
Our bolts are used by a broad range of industries requiring assemblies and fastening applications. These threaded fasteners can connect machine parts, mount equipment, and more. As a removable fastener, they also facilitate the regular maintenance and inspections that keep equipment running longer.

National Bolt & Nut Corporation offers both standard and custom bolts and fasteners to meet different grades and specifications. This ensures we can cover the full spectrum of our manufacturing customers' applications, including

  • Mining
  • Heavy equipment
  • Construction
  • Transportation
  • Automotive
  • Energy and alternative energy

 

TYPES OF BOLTS:

ANCHOR
Sometimes referred to as an L-bolt, the anchor bolt is common in concrete and masonry construction. When embedded in concrete structures or masonry fills, these bolts attach components and integral equipment to the solid structure of the building.

BENT
Bent bolts can be further broken down into the following categories based on the way they are bent and their intended application:

  • Eye bolts. The head of these bolts forms a full circle-like the eye of a needle-allowing for the attachment of cables, ropes or other fasteners.
  • Hook bolts. The unthreaded end of this bolt forms a hook shape that may range from a simple L-shape to more complex custom bends.
  • J-bolts. These J-shaped bolts typically act as a hook, facilitating easy attachment and detachment from other components or structures, often in combination with eye-bolts.
  • U-Bolts. This bolt is bent into the shape of a U with both ends threaded, enabling users to secure pipes or tubes to other components or structures.

 

CARRIAGE
Carriage bolts are commonly used to attach wood to metal. The carriage bolt may be distinguished by a square formation located under its smooth, rounded bolt head. This shape helps prevent it from turning during tightening.

COUNTERSUNK
Countersunk bolts have a sloped shoulder on the head, allowing them to fasten while leaving the head of the bolt flush with the attached surface. This provides a smoother exposed finish and allows moving parts to function within tight clearances.

ELEVATOR
This type of bolt includes characteristics of both carriage bolts and countersunk bolts. The head is undercut with a square shape to hold it in place during tightening, but it has a thinner head that can be made flush or near-flush with the attached surface.

LAG
These bolts include threads on only a portion of the bolt. This lack of threads is known as a lag. It facilitates a smooth surface attachment to wood, while the threaded end is more like a wood screw rather than a typical bolt thread designed to receive a nut.

T-HANDLE
When a bolt requires frequent handling by an operator without the use of a tool, a t-handle bolt is often the best option. These bolts have an extended head in the shape of a T, allowing for hand tightening or loosening.

T-SLOT
This type of bolt has a T-shaped head, but is not meant to facilitate tightening and loosening by hand. Instead, the T shape of this bolt fits into a slot in the attachment surface so that the bolt will not turn during tightening.

FLANGE
Sometimes called frame bolts, flange bolts are common for load bearing applications. The heads of these bolts are undercut with an integrated flanged washer face located under the head to distribute stress from a load over a broader area.

PLOW
A plow bolt combines a number of distinguishing features from other bolts into a durable fastener often used in structural situations. Plow bolts include a countersunk head, allowing flush mounting while undercutting the head with a square shank neck to hold the bolt in place during tightening.

 

Watch>>>Fastener Material Selection and Plating Guide
Learn how to choose the best Fastener Material & Finish for your project, what are the different Materials Properties, what is Galvanic Corrosion and more here

National Bolt & Nut, Inc.
National Bolt & Nut, Inc. (NBN) is a Domestic Manufacturer of large diameter custom non-standard fasteners for critical care applications.

NBN supplies Bolts, Nuts, Studs and Washers to the Agricultural, Energy, Heavy Equipment, Mining, Petrochemical, and Rock Crushing industries.

We have provided "blue print specials" since 1996 in all grades of steel and exotic materials.
Our ISO compliant Quality Program challenges NBN to identify ways to best serve ever changing customer needs. All fasteners are manufactured to ASME, ASTM, DIN, ISO and to customers proprietary standard specifications.

NBN guarantees to offer custom quality fasteners at the best price with the fastest industry lead times available.