Author Archives: Shelley Doherty

  1. Features of Shaft Collars: Three Unique Ways to Use a Shaft Collar

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    Shaft collars attach to shafts and other pieces of hardware to affix components in place. They can grip bearings in the right position, act as mechanical stops to halt rotary motion along the shaft, and ensure internal components don’t shift into misalignment. Because these components are so versatile, they come in a wide range of options for different industrial and commercial applications. 

    At Stafford, our experienced team of engineers specializes in creating sturdy, high-performance shaft collars for virtually any configuration. Learn more about the six most common types of shaft collars and their role in food processing, conveyance systems, and heavy-duty machinery.

    Types of Shaft Collars

    Depending on your machinery setup and your mounting needs, there are multiple different shaft collars available. These different varieties are classified based on how accessible the shaft is and the axial hold required. Clamp shaft collars, for example, clamp onto the shaft instead of requiring a set-screw for attaching to the shaft. Some of the most popular options include balanced, hinged, set screw, single split, double split, and threaded shaft collars. Take a deeper look at the different options: 

    • Set Screw Shaft Collars: This collar is solid. It doesn’t have any relief cuts, and it doesn’t split into different sections. Instead, the set screw shaft collar is put into position and then affixed to the shaft by a tightened set screw that runs from the outer to the inner diameter of the collar.
    • Single Split Shaft Collars: This type of collar has one slot opening that allows for sliding the collar onto the shaft and then clamping it down. The slot can be opened and closed with a hex screw. The advantage of this model is that it’s easy to install, however, it doesn’t have the same uniform gripping strength as two-piece clamping collars and cannot be used where the shaft end is inaccessible.
    • Double Split Shaft Collars: These two-piece collars have two halves that are joined together by two socket cap screws. This allows for easy installation, as they can be installed either axially or radially. They also have a more uniform distribution of holding power than one-piece split collars.
    • Threaded Shaft Collars: These collars have an internally threaded clamp so they can be installed over a matching threaded shaft. Not only do the threads ensure the placement is exactly right, but the shaft is designed for supporting heavy axial loads. Threaded shaft collars are available in both single-split and double-split varieties.
    • Balanced Collars: Balanced collars are built to reduce vibration and shaking on a spinning shaft. They also help ensure an even distribution of the load weight. They feature a design similar to a double-split shaft collar, but the attaching screws sit opposite each other to provide even distribution. 
    • Hinged Collars: Hinged collars have a triple-link hinge and a captive clamping mechanism. This allows the collar to open easily, be positioned and then clamped shut. As a self-contained unit, there is never a risk of loose screws.

    Each of these shaft collars can play a critical role in the integrity of your equipment or facility systems.

    Food Processing

    In food processing systems, shaft collars can help at every stage of production and packaging. Shaft collars can help ensure consistent spacing between moving and weight-bearing elements, including supporting weight-bearing components and ensuring gears stay in the correct alignment during operation. Some key applications include:

    • Guiding and stopping parts
    • Mounting, aligning, and spacing components

    At Stafford Manufacturing, we construct all of our shaft collars with a smooth, burr-free finish that mitigates the risk of buildup and bacteria. Our collars are available in several types of stainless steel, making them ideal for situations requiring corrosion resistance or the ability to withstand frequent washdowns.

    • Affordable Cost
    • Wide Variety of Materials
    • Mounting Capabilities
    • Variety of Styles to Suit your Needs
    • Alignment Capabilities
    • Easy Assembly 


    Shaft collars are common in conveyor systems because they ensure all of the moving parts stay in alignment and can handle the weight of different loads. One common application of shaft collars in conveying is to keep the rollers consistently placed and aligned. Shaft collars from Stafford are built with sturdy, long-lasting materials that comply with today’s construction and industrial regulations.

    Heavy-Duty Machinery

    Heavy-duty machinery, like cranes and bulk industrial equipment, needs large, heavy-duty shaft collars that can ensure adequate weight-bearing capabilities. Collars from Stafford are built to secure shafts and axles, support weight, and stop movement as needed for smooth system operation.

    Learn More About Shaft Collars From Stafford

    The team at Stafford Manufacturing is here to help provide the right shaft collars for any application, from food processing centers that need to tightly control the risk of contamination to paper and pulp facilities that manage heavy loads. Contact us today to learn more or request a quote to start your order. 


  2. Accommodating Bore Configurations for Your Shaft Collar or Coupling

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    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. 


  3. What Is the Best Coupling for a Mixer?

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    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.


  4. Installation Guide for Rigid Shaft Couplings

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    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.
    (Click to Expand)

    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.

  5. Overview of Non-Standard Materials

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    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

  6. What Is a Threaded Shaft Collar?

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    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.

  7. What Is Shaft Coupling Windup and Backlash?

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    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.

  8. What Is the Difference Between Rigid and Flexible Couplings?

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    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?

    (Click to Expand)

    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. 

  9. What is a Shaft Collar and How Does it Work?

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    Shaft collars hold and position mechanical components around a shaft or mount shafts, tubes, and pipes onto flat surfaces, Available in a variety of styles and from numerous material types, shaft collar selection depends heavily on the details of the intended application.

    Stafford Manufacturing is a premier manufacturer of shaft collars, clamps, and related mechanical components. This blog will explain shaft collars in more detail to help users make informed decisions when sourcing these critical components.


    How a Shaft Collar Works

    Commonly found in power transmission applications, shaft collars are ring-shaped plastic or metal devices that clamp around a shaft. The purpose of the collar is usually to hold motor components, gear assemblies, sprockets, bearings, and other parts in place and sometimes facilitate their proper movement. The collars may specifically locate components, keep them appropriately spaced, or limit their movement. Shaft collars may also be used to connect one end of the shaft itself to a part or surface.

    The simplest shaft collars use set screws that tighten into the shaft to hold the collar in place. While these collars still see some use, the screws tend to mar the shaft which makes it difficult to remove and reposition the collars. Most modern shaft collars use a clamp that holds to the shaft. Clamp screws tighten the clamp around the shaft without the need to dig into the shaft itself.

    There are multiple types of shaft collars, each suited to different purposes. Some of the most common types of shaft collars include:

    • Hinge shaft collars have an open hinge on one side and a clamp screw on the other, enabling them to be easily assembled anywhere on the shaft. They are completely self-contained and eliminate the risk of dropping or losing screws.
    • One-piece shaft collars feature improved performance, allowing an easy increase in clamping force by tightening the clamp screw.
    • Two-piece shaft collars can be assembled anywhere on the shaft, including between other shaft collars.

    Shaft collars are also available in multiple bore configurations, including round, threaded, hexagonal, and square. While off-the-shelf shaft collars are suitable for many needs, standard shaft collars can be altered to meet specific application needs. Fully customized shaft collars are also an option for unique situations.


    Applications of Mounted Shaft Collars

    Mounted shaft collars are used in numerous industrial applications. Common use cases for shaft collars include:

    • Positioning or aligning moving components, such as gears, bearings, and pulleys in automated industrial equipment
    • Securely connecting tubes to hardware
    • Mounting sensor components onto shafts
    • Providing mechanical stops for actuators, cylinders, and other varied components in vehicles and heavy equipment
    • Use as spacers or stops on laboratory equipment, such as frames and clamps
    • Guides, spacers, or stops on medical imaging machines such as MRIs and CAT scanners
    • Facilitating precision positioning in optical measuring equipment
    • Provide appropriate positioning of gearbox or motor components in power transmissions


    Shaft Collars From Stafford Manufacturing

    Since 1975, Stafford Manufacturing has been fabricating and distributing standard and custom shaft collars for use across industries and applications. We offer extensive customization capabilities in terms of design, material, and finishing choices. We offer end-to-end support for any shaft collar project, including in-house CAD design and engineering capabilities that enable us to tailor a shaft collar to meet the specific needs of any customer.

    Our facilities are compliant with all relevant industry standards, including ASA, ASME, ANSI B18.3, ISO 9001:2015, REACH, and RoHS. We work with customers in an expansive range of industries, such as:

    • Agriculture machinery
    • Assembly
    • Automation
    • Conveyor systems
    • Heavy trucks/off-road
    • Laboratory and research equipment
    • Machine tools
    • Marine
    • Medical equipment
    • Military and defense
    • Mining
    • Mixing equipment
    • Maintenance, repair, and operations
    • Oil and gas
    • Optical
    • Packaging
    • Retail displays
    • Robotics

    Our team can help you identify the appropriate shaft collar design, material, and finish for any application. To see how our team can support yours, please contact us or request a quote today.

  10. Differentiating Types 303, 304, and 316 Stainless Steel

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    Class 300 stainless steels are austenitic chromium-nickel alloys that are highly corrosion resistant and non-magnetic, displaying excellent formability and temperature resistance. Three of the most common austenitic stainless steels are types 303, 304, and 316. Although related, these alloys differ in areas like chemical composition, material capabilities, and cost.

    Type 303

    The base composition of type 303 stainless steel is approximately 18% chromium and 8% nickel. The additions of 0.15% sulfur or selenium and phosphorus make type 303 the most machinable alloy of the class but slightly reduce its corrosion resistance. Despite this, it is still an optimal material for components that require significant machining or tight tolerances, such as nuts and bolts, screws, bushings, fasteners, bearings, and more. Type 303 is regarded as a cheaper, more machinable alternative to similarly composed 304 stainless steel.

    Type 304

    The most commonly used austenitic stainless steel, type 304, is composed of 18% chromium and 8% nickel with low levels of carbon. This alloy is highly resistant to oxidation and corrosion, durable, and easy to fabricate. Considered the most versatile stainless steel of the class, type 304 has uses in a range of applications across diverse industries—from architectural details to kitchen appliances to automobile parts. Type 304 is easily accessible and less expensive than 316 stainless steel.

    Type 316

    Composed of slightly higher levels of chromium (16-18%) and nickel (10-14%) than types 303 and 304, the most distinguishable properties of 316 stainless steel come from the addition of 2-3% molybdenum, an element which significantly improves the alloy’s corrosion resistance. Type 316 also exhibits improved heat tolerance, resistance to creep and pitting, and excellent tensile strength. Known for its ability to withstand the effects of exposure to chlorides, the alloy is used extensively in chemical and marine applications, as well as a number of other industries. Type 316 has lower formability than 303 or 304 stainless steels, but its higher resistances make it more expensive to source.
    The characteristics responsible for differentiating these common class 300 stainless steels also uniquely position each alloy to perform for specific applications.

    Applications of 303 Stainless Steel

    The highly machinable, non-magnetic, and non-hardening type 303 stainless steel is well-suited to applications requiring tight tolerances and heavy machining, like in the manufacturing of small parts. Typical uses of this alloy include things like:

    Applications of 304 Stainless Steel

    The extreme versatility of type 304 makes it the most widely used stainless steel on the market. Offering exceptional corrosion resistance and durability, this alloy is suitable for a spectrum of uses across nearly every industry. Some of the most common applications are:

    Applications of 316 Stainless Steel

    Offering the greatest resistance to a variety of corrosive elements, type 316 stainless steel is the most appropriate alloy for applications with continuous exposure to harsh environments or where strength and hardness are a critical factor. This includes uses such as:

    • Stainless steel floats
    • Marine parts
    • Outdoor electrical enclosures
    • Chemical and pharmaceutical equipment
    • Medical devices and equipment

    Stainless Steel Components by Stafford Manufacturing Corp.

    Stafford Manufacturing Corp. is a global manufacturer and distributor of shaft collars, rigid shaft couplings, and specialty mechanical components used in OEM and MRO applications for industrial and consumer products. The inclusion of types 303, 304, and 316 stainless steels in our standard and custom components plays a pivotal role in enhancing their quality and durability. Our selection of stainless steel products includes:

    • Threaded bore shaft collars
    • Two-Piece Split Clamp Collars
    • Set Collars
    • Hinge Collars
    • Square and hexagonal bore shaft collars
    • Rigid shaft couplings and shaft adapters
    • Metric shaft collars, rigid shaft couplings, and components

    For additional information on stainless steel material considerations for your next application, or to learn more about the Stafford advantagecontact us today.