Category Archive: Uncategorized

Accommodating Bore Configurations for Your Shaft Collar or Coupling

Stafford Manufacturing Corp. designs and manufactures rigid couplings, shaft collars, and specialty mechanical parts used in automation, power transmission, motion control, and other OEM and MRO applications. We have collars and couplings available in square, threaded, hexagonal, keyed, and round bore configurations. In addition, we can add drive slots, press-fits, pulleys, or other special parts to meet your needs.

Here you’ll learn about each of these bore options and how to decide on the ideal shaft collar or coupling for your application. 


Types of Collar and Coupling Bore Configurations

Shaft collars and rigid couplings are machine components that slide over a shaft and lock into place with either set-screws or with clamping screws. They have three primary functions:

  • Holding components in place
  • Creating a connection between a shaft and another component
  • Positioning or locating parts along a shaft

Manufacturers supply variations of collars and couplings in different sizes, designs, and materials to fit a wide range of applications. Some of the common  shaft collar bore configurations include:

  • Round 
  • Threaded
  • Square
  • Hex
  • Keyed


Round Bores

As one of the most popular bore configurations, round shaft collars and couplings are used in various power transmission, motion control, and mounting applications. Serving as locators, spacers, bearing faces, or stops, they are most often used on shafts, tubing, pipes, and split hubs.

Round bore configurations are found in the following products:

  • One-piece shaft collars
  • Two-piece shaft collars
  • Hinge shaft collars
  • Threaded shaft collars
  • Heavy-duty shaft collars

Browse Stafford Manufacturing’s full selection of round bore shaft collars in our catalog

Browse Stafford Manufacturing’s full selection of round bore rigid couplings in our catalog

Round Bore Threaded Coupling
Round Bore Shaft Collar


Threaded Bores

Threaded shaft collars have a threaded interior that matches with certain threaded shafts. These provide superior grip, suitable for uses that require precise preload and location settings. Threaded shaft collars act as a stop to position parts or prevent them from moving along the shaft. 

Threaded bore configurations are found in the following products:

  • One-piece or two-piece split clamp UNF/ UNC Threaded Bore Shaft Collars
  • One-piece or two-piece Accu-Clamp™ Threaded Shaft Collars
  • One-piece or two-piece ACME Threaded Collars
  • One-piece or two-piece UNF/UNC Threaded Split Hub Collars
  • Threaded Hinge collars

See the threaded shaft collars we provide

Threaded Shaft Collar
Threaded Hinge Shaft Collar


Square and Hex Bores

Stafford Manufacturing produces hexagonal and square shaft collars and couplings to fit onto hexagonal and square-shaped shafts. Square and hex shaft couplings and collars are easy to install and customize with mounting capabilities if necessary. They provide high clamping power and are primarily used in food processing and conveyor systems. 

Square bore configurations are available in:

  • Two-piece split clamp styles collars
  • Mounting two-piece stackable styles collars
  • Precision Sleeve Rigid Couplings

Hex bore configurations are available in:

  • One-piece split clamp styles
  • Two-piece split clamp styles.
  • Precision Sleeve Rigid Couplings

Look through our full selection of hex and square shaft collars and couplings here.

Hex Bore Precision Rigid Coupling
Hex Bore Shaft Collar
Square Bore Precision Rigid Coupling
Square Bore Shaft Collar



Shaft couplings can be configured with keyways, but they are not always required. They should be utilized for couplings designed to support radial alignment and loads with high torque. Determine whether radial alignment or additional torque will affect the system’s overall operation, and then use that analysis to decide whether you need a keyway.

Keyed Rigid Coupling
Keyed Shaft Collar


Selecting Your Shaft Collar or Coupling Configuration

The right shaft collar or coupling is the one that fits your configuration and application.  In some cases, a certain type of configuration may be better than other options (i.e.  square, hex, and keyed shafts can handle more torque). Keyed shafts in particular have a locking position that makes accommodating higher torques possible.

Standard bores are cost-effective options that fit most basic applications. Stafford Manufacturing carries round, threaded, square, hex, and keyed bores as standard products, so our customers can rely on us to have what they need, when they need it. In addition, Stafford is the only stocking manufacturer of a full line of square and hex bore products.

While standard bore products serve most applications at the lowest cost, some applications require customized collars or coupling bores. Stafford has been manufacturing custom shaft collars and couplings for over 47 years and we can produce to your exact needs at a fair price with no minimum order quantity.

Stafford Is Your Custom Shaft Collar and Coupling Manufacturer

Stafford Manufacturing has nearly 50 years of industry experience. As an ISO 9001:2015-certified business, our staff has the quality control standards in place to produce the highest quality shaft collars and rigid couplings. We have a large selection of products, which enables us to assist you in selecting the ideal bore configuration for your particular needs and price range. If you can’t find a shaft collar or coupling that meets your needs, we will collaborate closely with you to design and produce a custom solution.

Contact us or request a quote today to learn more about our standard and custom offerings. 


How to Connect Shafts

 Shaft couplings play a key role in transferring power or torque for motors, pumps, compressors, conveyors, turbines, and other mechanical equipment. Rigid shaft couplings can achieve this goal and allow for different types of shaft connections. Stepped couplings can be used for connecting different size shafts.  Shaft adapters can solve compatibility issues, such as changes in shaft size or length. Inch-to-metric couplings can solve incompatibilities occurring when mating an English shaft to a metric one.  Custom shaft couplings and adapters can accommodate unusual variations or configurations not satisfied by standard products.

Stafford Manufacturing produces shaft collars, rigid shaft couplings, and specialty mechanical products for motion control, power transmission, automation, and other MRO and OEM applications. Here we’ll discuss how to connect shafts, including those with different sizes, measurement systems, and other specifications.


Two-Piece Split Clamp-Style Coupling

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What If I Have Two Different Sized Shafts?

Connecting shafts of different sizes is a common issue that can be solved with compatible rigid shaft couplings. Designed for perfectly aligned shafts, rigid shaft couplings mate shafts with identical or different diameters while maintaining high torque transfer and preventing backlash. Many configurations of our shaft couplings have stepped bores to connect shafts that differ in size. We offer standard and custom versions of these types of rigid shaft couplings:


Two-Piece Split Precision Sleeve Coupling with Keyways

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 What If Need a Close Tolerance Fit?

A close tolerance fit is a necessity whenever you are putting the coupling on a precision machined shaft. Precision sleeve couplings are uniquely suited for applications requiring extremely precise machined shaft alignment and a close tolerance shaft-to-coupling fit.


Stafford’s exclusive Precision Sleeve Coupling features a solid center section that provides a close tolerance fit on ground shafting, includes a keyway, and the Accu-Clamp™ design which incorporates integral self-centering clamping collars at both ends. This product assures shaft alignment with zero backlash. To assure precise shaft alignment, it maintains <.001″ TIR concentricity while in use. It is precision machined, non-marring, easy to adjust, with high clamping power.

Stafford offers the following types of Precision Sleeve Couplings:


Inch-Metric Conversion Coupling

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What If I’m Connecting an Inch Shaft to a Metric Shaft?

Inch-metric conversion couplings have a bore on one side measured in inches and the other side in a metric size. Stafford Manufacturing carries a full range of common sizes in our selection of inch-metric conversion couplings. External dimensions and screws are in inches. These couplings can be further modified to include keyways if needed.

Our inch-metric conversion couplings can mate inch and metric shafts with zero backlash and smooth bores, which protect the shafts from damage. They have superior torque capacity compared to set screw type couplings.

Stafford offers the following types of inch-metric conversion couplings:


Step-Up Shaft Adapter

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What If I Need a Shaft Adapter?

While shaft couplings can connect shafts of different diameters, shaft adapters enable connections when:

  • One or both shafts are not long enough to be effectively connected with a coupling
  • Shafts differ in diameter and a coupling does not accommodate the difference
  • Shaft damage would result in a poor transfer of power or motion
  • Shaft replacement is not recommended due to cost or other considerations

Available in step-up or step-down configurations, shaft adapters act as both an extension to an existing shaft and as a way to increase or decrease shaft diameter using a straight-bore or standard stepped-bore coupling. Our rigid shaft adapters use a clamp-style attachment to avoid shaft damage and come in keyed and keyless styles. 


Rigid Shaft Coupling Configurator

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None of These Work for Me — What Do I Do?

Uncommon sizes or combinations of shaft diameters, shapes, keyways, or other configurations can be solved with custom shaft couplings or adapters, avoiding the need for complete shaft replacement or system reconfiguration. Customers can custom-design couplings through our rigid shaft coupling configurator tool, which can provide product recommendations based on your specifications.

Because manufacturing custom parts is our specialty, our expert team welcomes requests for customized rigid couplings to meet your precise requirements. Custom modifications we commonly make include:

  • Bores: adjustments for special diameters, keyways, and threadings
  • Outside Diameters: surface modifications (e.g. knurling, flats, pulley grooves, notches)
  • Holding Power: adjustments for extra heavy-duty operation
  • Circumferential Keyways: to control axial shift
  • Shaft Shapes: to connect different shaped shafts
  • Balancing: to minimize misalignment, vibration, and wear
  • Materials & Finishes: meeting customer material or surface finishing requirements
  • Shaft Extenders: to accommodate length, duty, configuration, or other needs

Customers may also modify our fully machinable Shaft Adapter Max to meet their specific needs. It is available with keyways or without, offering multiple configurations to easily extend and adapt for hex, square, or threaded shafts.

Custom Fabrication by Stafford Manufacturing

At Stafford Manufacturing, we pride ourselves on our wide range of standard shaft couplings, collars, adapters, and related products. Our innovative designs, extensive catalog of stock components, and customization capabilities illustrate our commitment to industry-leading components and customer service. Contact us to learn more about our standard and custom components for power transmission, motion control, automation, and related applications, or request a quote for your next project.



Stafford Manufacturing Corp.

256 Andover St.

Wilmington, MA 01887

Phone: 978.657.8000




What Is the Best Coupling for a Mixer?

large industrial batter mixerMixers are common industrial devices that consist of a motor and a propeller or paddle with a coupling acting as the connection point. Mixers are flexible, adaptable pieces of equipment found in a range of industries, from food processing to mining to chemical facilities.

Choosing the correct coupling for a mixer can be challenging as it needs to have an exact, rigid fit . This blog will highlight how to determine the right coupling for your mixer and how our configurator tool can help you configure your rigid coupling to your needs.


What Is a Rigid Coupling?

Unlike flexible couplings, a rigid coupling does not allow any radial or axial motion between the driving shaft and the driven unit. It is primarily used for vertical applications. Rigid coupling types include:

  • One-piece split couplings when there is access to both the motor shaft end and the paddle attachment.
  • Two-piece split couplings for easy assembly when in-line installation is needed.
  • Three-piece split couplings when the end of the shaft will remain fixed while the other is moved or changed (very common for mixer situations when paddles would be changed or replaced).
  • Flanged couplings when mounting options are needed.

On mixers, the motor is bearing-supported, but the shaft on the impeller side is not. Using a flexible coupling would require close bearing support on the paddle, but the sleeve-like design of rigid couplings eliminates the need for a bearing to support the paddle. This makes rigid couplings the only viable option for mixers.

Rigid couplings have a simple and durable design, allowing greater transmission of power to mixers. They are more cost-effective than other options and offer more design flexibility. While requiring exact alignment between shafts, rigid couplings offer a stronger connection, higher torque, and more precision than flexible couplings.


havey duty rigid shaft coupling wiht a havy duty mixer in the backgroundAdvantages of Rigid Couplings for Mixers

Rigid couplings provide advantages, such as:

  • Excellent Torque Transmission: They can transfer torque efficiently between connected shafts.
  • Low Production Costs: Manufacturers such as Stafford Manufacturing can produce custom and standard rigid couplings at affordable prices.
  • Torsional Stiffness: Its high torsional stiffness enables better positioning.
  • High Precision: Rigid couplings offer high precision with almost no windup or backlash.
  • Alignment Capabilities: They can establish shaft alignment between the connected parts and the motor.
  • Easy Assembly: Rigid couplings have a simple design, allowing for easy assembly, disassembly, and maintenance operations throughout the coupling’s lifespan. 


Considerations for Selecting a Rigid Coupling for a Mixer

Choosing the best coupling for a mixer requires precision. Stafford Manufacturing’s configurator tool can help you customize a rigid coupling that suits your exact needs. Configure it by bore diameter, coupling style, coupling material, screw material, finish, and other options available upon request.

Here are more details about the top considerations for choosing a rigid coupling for a mixer.

Bore Diameter

Bore diameter ranges from ¼” to 4”. Choosing the right diameter is key to ensuring a  precise alignment.  

Coupling Style

Coupling styles include one-piece, two-piece, and three-piece. One-piece styles have high torque capacities, unlike set screw type couplings. Two-piece styles allow for easy assembly and adjustment. Three-piece styles are used to maintain one shaft’s positioning while the other is adjusted.

Material Selection

Material selection is based on the substance your coupling is exposed to. Coupling materials include brass, 303 and 304 stainless steel, weldable steel, carbon steel, and 2024 aluminum.


How to Choose the Best Coupling for a Mixerrigis shaft couplings for mixers

Consider these factors when deciding on the best coupling for your mixer:

  • Shaft size
  • Keyway size if needed
  • Required torque capacity
  • Bore diameter
  • Material requirements for specialized (i.e. food-grade) applications

Stafford’s rigid couplings meet these criteria as they are designed with end users’ needs in mind. Our rigid couplings come in different types, from the common one-piece split clamp coupling to precision sleeve couplings.


Choose Stafford as Your Coupling Manufacturer

Stafford is the leading manufacturer of high-quality shaft couplings and rigid couplings. With the help of our configurator tool, you can determine the right rigid coupling for your needs. Contact us to learn more or request a quote for our products.


General Precision Products

General Precision Products at Stafford

Stafford offers several types of general precision products including both machined components and sheet metal components and enclosures. A wide variety of options are available and can be custom designed to meet your unique applications.

  • Machined components. Machined components are created using various precision machining processes, such as CNC milling, waterjet cutting, laser engraving, welding, CNC turning, and more. Machined components are used throughout demanding industries that require extremely tight tolerances and high part-to-part repeatability. 
  • Sheet metal components. Sheet metal components are produced using techniques like bending, cutting, punching, welding, and more. Whether your application requires simple parts, mated assemblies, or full enclosures, Stafford’s sheet metal fabrication meets your exact requirements .
  • Enclosures. Off-the-shelf enclosures can be modified with processes like laser cutting, MIG/TIG welding, robotic welding, and more. Many industries like biomedicine and aerospace rely on fabricated enclosures to protect sensitive components.


Our machined and sheet metal components are used in countless industries, especially those requiring highly accurate and repeatable parts. Depending on the particular industry, general precision products can be either simple or complex and can be made in a variety of sizes and shapes to fit different needs. 

Examples of industries that rely on general precision products from Stafford Manufacturing include:  

  • Aerospace
  • Biomedicine
  • Construction
  • Mining
  • Pulp & Paper
  • Medical
  • Optical
  • Automation

Capabilities: Stafford Manufacturing

At Stafford Manufacturing, our general precision capabilities include a range of machining and sheet metal fabrication processes. We can produce components in various sizes, shapes, and complexities to meet the needs of diverse industries. 

Our precision machining capabilities include:

  • CNC Milling
  • CNC Turn Mill
  • CNC Turning
  • CNC Bar-Fed Lathes
  • Waterjet Cutting
  • Laser Engraving
  • Welding
  • 3D Prototyping
  • Prototyping Machining

Our sheet metal fabrication capabilities include:

  • Bending
  • Cutting
  • Laser Etching
  • Punching
  • Welding
  • Hardware Insertion

Additionally, we deliver a range of secondary processes, including painting, plating, assembly, silk-screening, and more.

Finished Products for Complete Applications

Many advanced industries rely on precision products for various applications. At Stafford Manufacturing, we have the capabilities to deliver high-quality, accurate products using various machining and sheet metal fabrication techniques. Through our expertise and extensive capabilities, we can deliver the components you need with the utmost precision and repeatability. 

For more information about our general precision products and other capabilities, contact us or request a quote today.

Installation Guide for Rigid Shaft Couplings

Stafford Manufacturing Corporation is a leading manufacturer and distributor of a variety of shaft collars, specialty mechanical components, and rigid shaft couplings for use in many types of applications. At Stafford Manufacturing Corp., we offer a wide range of rigid couplings to allow two shafts to function as one.

When deciding on the right coupling for your application, one key factor will be whether you need a one-piece,  two-piece or three-piece coupling. One-piece clamp couplings offer zero backlash and feature high torsional holding power with no damage to the shafts. Two-piece couplings feature the same advantages, with the added benefit of allowing in-place service. Three-piece couplings allow you to keep one shaft in place while the other is changed.

In this guide, we’ll detail the steps for proper shaft coupling installation for the main types of rigid couplings, along with some factors that determine which couplings to use.


Based on an application’s specific requirements, rigid shaft couplings can consist of a vast array of materials, including 303, 316, and 304 stainless steel, 2024 aluminum, carbon steel or black oxide-finished carbon steel, or brass. The installation steps for rigid couplings will differ depending on the coupling type (one, two or three-piece).

Installation of a One-Piece Rigid CouplingInstallation of a One-Piece Rigid Coupling

The steps for installing a one-piece rigid coupling are as follows.


Rigid couplings are used when an application requires coupling of two aligned shafts (they can be shafts of the same sizes or different sizes). High stress could result if axial or radial misalignment takes place, potentially causing failure so they are only to be used with unsupported or fully aligned shafts. Once connected to two shafts, rigid couplings will prevent any relative motion from occurring. One-piece rigid couplings ensure alignment.

Installation Process

When installing a one-piece rigid coupling, take these steps:

  1. Wipe any excess dirt or oil off the shaft as well as the  bore of the coupling.
  2. Slide one end of the coupling over its mating shaft until that shaft is 1/32” short of the cross slot
  3. Adjust the center screw to half of the recommended seating torque.
  4. Adjust the outer screw to half of the recommended seating torque.
  5. Slide the other shaft into the remaining end of the coupling until it is 1/32” short of the cross slot.
  6. Adjust the center screw to half of the recommended seating torque
  7. Adjust the outer screw to half of the recommended seating torque
  8. Use a torque wrench to fully adjust all screws to the recommended seating torque, going from the center screws to the outer screws.
  9. If possible, slowly rotate shafts to ensure proper alignment.


Installation of a Two-Piece Rigid CouplingInstallation of a Two-Piece Rigid Coupling

The steps for installing a two-piece rigid coupling are:


Like one-piece rigid couplings, two-piece couplings are used to join two aligned shafts. The use of a two-piece coupling allows installation while both shafts remain in place.

Installation Process

The steps for installing a two-piece rigid coupling are:

  1. Wipe any dirt or excess oil off shafts and coupling bore.
  2. Assemble the top and bottom halves of the coupling over the two shafts, making sure that the ends with the face groove are together.
  3. Assemble the two-piece coupling to the point where there is mild resistance in the screws.
  4. Use a torque wrench to adjust the center screws to half of the recommended seating torque.
  5. Use the same wrench to adjust the outer screws to half of the recommended seating torque.
  6. Use the torque wrench to adjust all screws until they’re at the full recommended seating torque, starting with the center screws and completing the process with the outer screws.
  7. Ensure the clamping is even by checking that the slot  gap is the same on both sides
  8. If possible, slowly rotate shafts to ensure proper alignment.
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Installation Guide for Rigid Shaft Couplings


Installation of a Three-Piece Rigid CouplingInstallation of a Three-Piece Rigid Coupling

The steps for installing a three-piece rigid coupling are:


Designed for aligned shafts, the three-piece clamp coupling makes two shafts function as one. It can remain fixed to one shaft while the other is moved or changed, or come completely apart to allow the most convenient assembly and adjustment.

Installation Process

The following are the steps for installing a three-piece rigid coupling:

  1. Wipe any dirt or excess oil off shafts and coupling bore.
  2. Assemble the ends of the coupling with the matching face groove onto its mating shaft
  3. 3. Use a torque wrench to adjust the center screws to half of the recommended seating torque.
  4. Use the same wrench to adjust the outer screws to half of the recommended seating torque.
  5. Mate the other shaft with the open end of the coupling and loosely assemble the coupling top, making sure that the machined end is towards the outside..
  6. Use the torque wrench to adjust the center screws to half the recommended seating torque
  7. Use the same wrench to adjust the outer screws to half the recommended seating torque.
  8. Use the torque wrench to adjust all screws until they’re at the full recommended seating torque, starting with the center screws and completing the process with the outer screws.
  9. Ensure the clamping is even by checking the saw slot gap.
  10. If possible, slowly rotate shafts to ensure proper alignment.


High-Quality Rigid Shaft Couplings from Stafford Manufacturing Corporation

If your application requires rigid couplings, please check out our wide variety of couplings, precision couplings, and shaft adaptors at Applications include motion control, power transmission, automation, and other types of MRO and OEM applications for consumer or industrial products.

To find out more about our products and custom capabilities, contact us today with any questions or request a quote for our products.

Overview of Non-Standard Materials

Since 1975, Stafford Manufacturing Corp. has been a leading manufacturer and distributor of shaft collars, rigid shaft couplings, and specialty mechanical components. Our products are used for industrial, consumer, OEM, and MRO applications, including automation, power transmission, motion control, and many others. We have unique expertise in designing components with non-standard materials that meet the needs of unique or challenging applications. Some of the non-standard metals we work with include:

  • Titanium
  • Nylon
  • Bronze
  • Brass
  • Delrin
  • High Temp Alloys


Titanium is a natural element with the highest strength-to-density ratio of any metal and a tensile strength ranging from 30,000 psi to 200,000 psi. This low-density, strong, and lightweight material exhibits a high melting point, low heat-induced dimensional change, good heat transfer, and high electrical resistance. Titanium is commonly used for airplanes, missiles, rockets, and various other applications such as springs and medical manufacturing due to its excellent elasticity, non-toxicity, and biocompatibility.


Nylon has high abrasion resistance, good thermal resistance, high machinability, good fatigue resistance, and noise dampening capabilities. The different nylon grades include 66, 11, 12, 46, and 6, which are named for the length of their polymeric chains. Key benefits of nylon include low internal stresses, lower water absorption, more crystalline structure equating to higher mechanical strength, and a higher melting temperature.


This copper and tin alloy is brittle, highly ductile, has low friction, doesn’t produce sparks when struck, expands as it hardens from liquid to solid, and produces a colored patina as it oxidizes. It is used in architectural structures and design elements as well as coins, bearings, electrical contacts, ship propellers, and shaft collars. Bronze can also be made into wool, avoiding some of the problems that steel wool presents, such as rust, broken filaments, and magnetic characteristics that can affect equipment. 


This gold-colored copper and zinc alloy has excellent electrical conductivity, good machinability, and low friction. It is commonly used in architecture and manufacturing of gears, locks, pipe fittings, and musical instruments. There are many subtypes and finishes available, including electroplating, powder coating, painting, and polishing. Tolerances are +/- 125 μm (standard), as well as +/-100 μm and +/- 50 μm (achievable).


Delrin is a plastic alternative to metal that offers good dimensional stability, excellent machinability, and high fatigue endurance. Natural-grade Delrin is NSF, FDA, and USDA compliant. 

Other qualities include:

  • Tensile strength of 6,000-22,000 psi
  • Impact strength of  .75-2 ft-lb/in. 
  • Heat deflection of 180-300ºF
  • Chemical resistance to fuels and solvents
  • Low moisture absorption
  • Good wear and abrasion properties
  • Superior impact and creep resistance
  • High strength and stiffness properties

Common components made from Delrin include gears, bearings, bushings, shaft collars, rollers, fittings, and electrical insulator parts. 

High-Temperature Alloys

High-temperature alloys are a mixture of at least one metal and another element that can withstand temperatures above 500º C. High-temperature alloys are used extensively in the military, medical, aerospace, and electronics industries. The alloys were designed for use in conveyors, furnaces, ovens, and oil and gas applications. They are costly and difficult to machine and shape. However, they are necessary for certain conditions. Stafford offers high-temperature alloy shaft collars in one piece, two piece, hinged, and flanged designs.

Specialty Mechanical Components from Stafford Manufacturing Corp.

Stafford Manufacturing Corp. is a leading manufacturer specializing in custom-manufactured shaft collars and rigid couplings in non-standard materials. To learn more about our products, please visit our product overview page. For pricing, please request a quote

Prototyping Parts and the SPARC Program Solution

Prototyping new parts isn’t always an easy endeavor even for experienced manufacturers. The process of producing, testing, and evaluating new components takes quite a bit of time and effort for all involved. As necessary as prototyping is, the traditional path for it is anything but efficient. Thankfully, Stafford Manufacturing is helping to change that with the new SPARC program. Read on to learn more about the various challenges of mechanical prototyping and how the SPARC program is tackling them.

What are the Challenges of Prototyping?

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What are The Challenges of Prototyping?

There are many challenges that manufacturers face when custom prototyping. These include:

  • Development time. Prototypes often require significant amounts of development time, both initial and for continued testing. New products go through several stages of development, but each new stage inevitably costs quite a bit of time, money, and effort.
  • Prototyping expenses. The more development time and hardware the prototyping process requires, the more expensive it will be.
  • Production problems. During the prototyping process, certain production issues may arise such as process issues, shortages of materials, material incompatibility with the design, and accuracy issues in the prototyped design versus the original blueprint.
  • Software issues. When converting original design files into a CAD model, there is often a risk of defects such as data loss. This greatly affects the surface quality and overall precision of the prototype. 
  • User confusion. A design may work on paper but be harder to put into action when in the hands of a user. Changes from the original design to the current one can also be a source of confusion if certain features are missing. 

The Stafford Prototype and Repair Collar System (SPARC)

Stafford Manufacturing Corp. Introduces Prototype and Repair Collar SystemPrototype manufacturing can be greatly simplified by using Stafford Manufacturing’s new SPARC program. SPARC is a 3-D printing solution to mechanical prototyping, allowing manufacturers to quickly produce models of shaft collars at a fraction of the cost and effort. 3-D printed models such as these can be created in only a few hours, greatly reducing both the amount of production time as well as the downtime in between production. This also means faster testing and faster feedback on designs, which further cuts design time.

The SPARC system provides a precision-machined Master Collar, available in one-and two-piece split clamp styles, in three OD sizes, in Steel, Stainless Steel and Aluminum, and is designed to accept a customized 3D printed insert. This provides a great amount of variety for testing new designs while keeping prototypes to a precise standard. The 3-D printed prototypes do not compromise on quality, allowing testers to get a sense of how the final version of the collar will operate. Additionally, Stafford Manufacturing assists manufacturers by providing a free library of shaft collar designs to use for prototyping, saving time that would otherwise be used in designing a custom collar.

Stafford Manufacturing for Prototyping Parts

Prototyping can be a costly, tedious, and imprecise venture, but Stafford Manufacturing’s SPARC system of 3-D prototype generation is set to change that. Providing many of the things that traditional prototyping lacks (accuracy in design, ease of manufacturing, lower costs, quicker manufacturing, etc.), SPARC enables more effective testing and a better end product.

To learn more about SPARC, contact Stafford Manufacturing today. As industry leaders in prototyping and manufacturing shaft collars, rigid shaft couplings, and other specialty mechanical parts, we have the experience and skill needed to provide excellent results at fair prices.

What Is a Threaded Shaft Collar?

A shaft collar is a simply-designed machine component composed of a plastic or metal ring fitted around a rod to act as stops, spacers, or for mounting components.  The collar can be loosened or tightened around the shaft using a clamp screw or multiple screws. They are used for tasks ranging from bearing loads to holding components in place along a rod. Among the many types of shaft collars are threaded shaft collars, which offer unique features that make them suitable for various applications. 

What Is a Threaded Shaft Collar?

Threaded Bore Shaft Collars

A threaded shaft collar is a type of shaft collar defined by the threaded 

pattern on the inside of the ID. While the standard shaft collar has a smooth interior, threaded shaft collars employ this textured interior to provide superior grip to the rod it is attached to. 

Threaded shaft collars are paired with a threaded rod, making them fasten together much more securely than a smooth shaft collar on a smooth rod. This provides higher axial holding power with less chance of damaging the rod. Additionally, threaded shaft collars allow for precise positioning and easier adjustments along the rod’s length.

In terms of variants, threaded shaft collars are typically manufactured in two distinct styles. The one-piece clamp collars are designed as a singular piece of equipment, which are fastened by being pressed together and then tightened once in position. Two-piece split collars consist of two separate halves of a single collar held together by a pair of screws that can be used to loosen and tighten the ring. Threaded shaft collars are typically made from steel or hard plastics. HInged threaded collars are also available for a simple, all-in-one assembly style.

Applications of Threaded Shaft Collars

threaded shaft collar

Due to the various advantages threaded shaft collars have over smooth 

shaft collars, they are typically used in applications where additional precision or strength are required. In machinery, threaded shaft collars are most frequently used for load-bearing applications and as spring tensioners. Their holding power and durability allow them to survive longer when placed under high stress than other similar parts. They are also used as end stop positioners and as limiters in repetitive operations.

Hospitals and other medical facilities make use of threaded shaft collars in places ranging from surgical equipment to beds and equipment stands. Other applications include:

  • Automation machinery
  • Mechanical stops
  • Locating components
  • Sprocket hubs
  • Bearing holders
  • Shaft protectors
  • Measuring and testing equipment

Stafford Manufacturing’s Threaded Shaft Collars

Stafford Manufacturing produces a variety of threaded shaft collars, all made with quality materials and designed to be non-marring to the rods they attach to. In addition to the previously touched upon UNF/UNC one-piece and two-piece clamps, Stafford also makes hinged collars that combine the ease of use of the one-piece collars with the quick assembly and disassembly of the two-piece collars. Our other offerings include ACME threaded collars featuring left- and right-hand threading as well as custom manufacturing options. 

Partner with Stafford Manufacturing

The many beneficial features of threaded shaft collars make them useful in many industries. Their superior grip strength and reliability compared to other types of shaft collars make them the optimal choice for a variety of applications. At Stafford Manufacturing, we manufacture superior threaded shaft collars and other types of shaft collars, and we can work with you to create a custom solution for your needs. For more information, or to get started on your next shaft collar solution, contact us today.

What Is Shaft Coupling Windup and Backlash?

Rigid shaft couplings connect two separate shafts by clamping onto their adjacent faces. When installed properly, the shaft coupling connects the shafts in a precise line that transfers rotary motion between the shafts without causing misalignment or breakage. However, there are two main obstacles to the perfect transfer of rotary motion:

  1. This occurs when the application of torque results in greater shaft rotation at one end compared to the other.
  2. Backlash is the unwanted reactive motion between connected mechanical parts that can break couplings or cause mechanical stress.

This blog explores the causes and effects of windup and backlash in shaft couplings.

What Is Torsional Rigidity in Shaft Couplings?

Windup, otherwise known as torsional deflection, occurs when torque is applied and the rotation of one end of the shaft is greater than the other end. This creates unequal torsional deflection that engineers have to consider as they set up feedback mechanisms. The varying load on the gears causes unequal wear. Torsional rigidity can also put stress on the coupling, leading to deformation, breakage, and a more frequent need for parts replacement.

What Is Backlash in Shaft Couplings?

Backlash occurs whenever mating parts in a system aren’t precisely aligned. In shaft coupling systems, the coupling may have a poor grip on each of the shafts, resulting in slight angles and unequal wear and stress on the system.

Shaft couplings can accommodate some degree of backlash, but it’s important to ensure that any backlash is well within the system’s threshold. For example, angular movements greater than 2° past the preferred angle are considered excessive backlash, and this can cause extreme wear, stress, and even breakage. Although not all backlash is bad, when the backlash is too great, it will result in erratic dial indicator and laser alignment readings. Operators should always reduce the backlash to within the 2° threshold before alignment begins.

There are different types of misalignment based on the resulting misalignment angle. These include:

  • Angular misalignment. When the shafts of two coupled units form a wide ‘V’ or obtuse angle
  • Parallel misalignment. When the shafts are parallel but one is slightly higher than the other
  • Skewed misalignment. Involves both parallel and angular misalignment

Any type of misalignment can cause backlash on the mechanical parts. It can also reduce the overall efficiency of the rotary motion transfer. It’s important to choose the right type of coupling that can prevent misalignment in the first place. Rigid shaft couplings, along with precise installation and setup, can reduce the risk of parts slippage and skew during operation of the system.

Choose Stafford Manufacturing for Shaft Couplings and Mechanical Components

At Stafford Manufacturing, we specialize in manufacturing rigid shaft couplings and other types of specialty mechanical components for energy transfer, motion control, automation, and other systems. Our rigid shaft couplings are designed to optimize the transfer of rotary motion. Browse our selection of one-piece split clamp, two-piece split clamp, three-piece split clamp, and precision sleeve couplings, or contact our team to learn more about our capabilities and inventory.

What Is the Difference Between Rigid and Flexible Couplings?

There are two main types of couplings: rigid couplings, which connect two shafts with a solid and high-precision hold, and flexible couplings, which can be used to connect slightly misaligned shafts but which can’t provide the same level of torque transfer. While both coupling types have their advantages and disadvantages, it’s important to know which coupling to choose in a particular application.

How Do Rigid Couplings and Flexible Couplings Differ?

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Difference Between Rigid and Flexible Couplings

Ultimately, the key difference between rigid and flexible couplings is in the connection they provide. Rigid couplings provide a rigid connection; the two shafts are firmly connected, and the coupling allows for a smooth transmission of torque throughout the system. Flexible couplings create flexible connections, and the components can lose some of the torque power through the interaction. While metallic flexible couplings offer greater torque capability than other flexible couplings, some torque is still lost.

Other important differences between rigid and flexible couplings are:

  • Alignment Requirements: Flexible couplings can handle slightly misaligned shafts. Rigid couplings are torsionally stiff and can’t tolerate any misalignment. This applies to both shafts that are physically misaligned at rest and parts that may cause misalignment during operation due to thermal changes.
  • Backlash: Rigid couplings, especially newer models of aluminum rigid couplings, can significantly reduce backlash to at-zero or near-zero levels. Flexible couplings don’t offer the same protection.
  • Maintenance Requirements: Because rigid couplings are stiff, they do not absorb vibrations, which can lead to early wear on parts that aren’t properly aligned. Operators should routinely check rigid couplings for wear and alignment, and they should also routinely apply lubricant. Flexible couplings can handle vibration and shock without adverse wear.
  • Complexity: Flexible couplings often have more components and/or are more complex. This can make operation and maintenance more complicated. Rigid couplings are more simple and straightforward in comparison.
  • Applications: Flexible couplings can be used in servos with low or moderate torque levels and the potential for shaft misalignment. This includes applications such as machining tools, semiconductor manufacturing, and packaging equipment. Rigid couplings work best for high-torque requirements, shaft support applications, and push-pull use cases.
  • Cost: Rigid couplings are more affordable than flexible couplings, which tend to have a high cost.

Advantages of Rigid Couplings

Both rigid and flexible couplings have their place in almost any complex motion system. However, rigid couplings provide several advantages over their flexible alternatives that make them the preferred choice for many projects. Some of their key advantages include:

  • Excellent torque transmission: Rigid couplings can efficiently transfer torque from one shaft to the other connected shaft.
  • Low cost of production: Manufacturers can produce standard and custom rigid couplings at cost-effective rates.
  • Precision, with nearly zero windup and zero backlash
  • Torsional stiffness: High torsional stiffness allows for better positioning. 
  • Simplicity
  • Alignment capabilities: Rigid couplings can be used to establish shaft alignment between the motor and connected components.
  • Suitability for push-pull and support applications
  • Easy assembly, disassembly, and maintenance operations throughout the life of the coupling

High-Quality Rigid Couplings From Stafford Manufacturing

Rigid couplings provide excellent torque, minimal backlash (with some of our standard couplings providing zero backlash), and high torsional stiffness. This makes them ideal for a wide variety of precision applications that need high levels of power. At Stafford Manufacturing, we manufacture and supply our clients with high-quality rigid couplings for a range of applications. Learn more about how to choose the right rigid coupling for your needs, or browse our catalog to find the right products today.