How Precision Shoulder Screws are Used in Robotics and Automation

Precision shoulder screws have become an indispensable component in the realm of robotics and automation. Their unique design, combining the functionality of a fastener and a shaft, empowers engineers to achieve precise positioning, smooth motion, modularity, and stability within robotic systems. By incorporating shoulder screws, designers can elevate the performance of robots, making them more reliable, accurate, and adaptable to meet the growing demands of various industries. In this blog, we will explore how precision shoulder screws are used in robotics and automation, and what factors to consider when purchasing them for industrial applications.

What are Precision Shoulder Screws?

Precision shoulder screws are a type of fastener designed with a cylindrical shoulder that provides precise alignment and support, making them ideal for use in applications that require accurate positioning and secure attachment.

When selecting these screws for industrial applications, it is important to consider factors such as material, size and thread type, head type, and application requirements to ensure that the screws provide the necessary strength and support, and can withstand the forces and stresses involved in the application. With the right precision shoulder screws, robotics and automation applications can operate with precision, accuracy, and reliability. Our handy Buyer’s Guide (link to guide)can direct you to the most common off the shelf available options.

Precise Positioning & Alignment

One of the primary benefits of precision shoulder screws is their ability to provide precise alignment in robotic and automation applications. The shoulder of the screw acts as a guide for the mating component, ensuring that it is aligned precisely and securely. By using shoulder screws, engineers can achieve tight tolerances, eliminating any unwanted play or misalignment that could compromise the robot’s performance.

Secure Attachment

Another key benefit of precision shoulder screws is their ability to provide secure attachment. The shoulder of the screw creates a stop against the mating component, preventing it from moving or rotating. This is important in applications that involve high levels of vibration or stress, as it ensures that the components remain securely attached and in place.

Smooth and Reliable Motion

In robotics, smooth and reliable motion is essential for efficient and accurate operations. Precision shoulder screws facilitate this by reducing friction and ensuring smooth movement between connected parts. The shoulder section acts as a bearing surface, minimizing wear and tear while allowing the robot to perform intricate tasks with minimal resistance. This enhanced motion control enables robots to execute precise actions, such as pick-and-place operations, assembly tasks, or complex maneuvers, with exceptional accuracy.

Modularity and Flexibility

Robotic systems often require modular designs, allowing for easy maintenance, upgrades, or customization. Precision shoulder screws excel in such scenarios due to their modular nature. By utilizing shoulder screws, different components can be connected and disconnected swiftly and securely. The screws enable the easy removal and replacement of specific parts or modules, providing a flexible platform for reconfiguration or adaptation to changing operational requirements.

Vibration Damping and Stability

In many robotic applications, vibrations can adversely affect performance and accuracy. Precision shoulder screws play a vital role in dampening these vibrations and maintaining stability. The shoulder section acts as a barrier, absorbing and dissipating vibrational energy, thus reducing the impact on the overall system. This feature is particularly crucial in high-speed or precision-focused robots where even slight disturbances can lead to errors or malfunctions.

Conclusion: Precision shoulder screws have become an indispensable component in the realm of robotics and automation. Their unique design, combining the functionality of a fastener and a shaft, empowers engineers to achieve precise positioning, smooth motion, modularity, and stability within robotic systems. By incorporating shoulder screws, designers can elevate the performance of robots, making them more reliable, accurate, and adaptable to meet the growing demands of various industries.

How to order

Precision Shoulder Bolts often show up under their OEM brand name.  Some of the most popular brands include: BERG, Concord, Globe, PIC, Lyn-tron and RAF. A comprehensive selection of Shoulder Screws is also offered by McMaster-Carr (tight tolerance series), MSC and Grainger. Finally, Precision Shoulder Screws can also show up under their Mil-spec numbers, which include MS51575 & MS51576 and are DFARS compliant with full paperwork.

Check out our Buyer’s guide for more info.

For more detailed information on Precision Shoulder Screws, visit us at our website or Request a Quote today, and our MF Supply team of sourcing experts can help you find what you need. “Finding the right screw for you” is our tag line after all!


Book a one-on-one consultation with our President, Robin, to discuss how MF Supply can help you solve your Industrial Sourcing, Fastener, and Safety concerns.


MF Supply Work With Us

Six Reasons To Buy From MF Supply

  • Full eCommerce Enabled Website With Technical Manual Available 24/7 – Visit our website and Create a New Account, track online orders, browse our product catalog, check technical specs, subscribe to our blog, or buy online.  We are adding items and improving functionality daily!
  • Same Day Shipping From The USA – Our hardware products are in stock and ship to you directly from our USA based distribution centers. 
  • Functional Equivalents To Expensive Brand Names- We stock and source alternatives to brand name fasteners, reducing long lead times and saving you money.
  • Creatively Solve Problems – We are sourcing experts, offer competitive pricing and specialize in finding hard to find parts and reducing long deliveries.
  • One-Stop Shopping On Certified Hardware – We stock and source a full line of fasteners including Mil-Spec, DFARS compliant and other industrial products.
  • WBE/WOSB Woman Owned Certified Small Business – To meet your diversity & set-aside needs.

MF Supply is a WBE/WOSB certified supply chain partner to business, industry and government.  We are sourcing experts and stocking distributors of Hardware, Precision & Mil-Spec Fasteners and Safety supplies.  For more than 50 years, we have been supplying manufacturers in the electronics, industrial, commercial, aerospace and military markets with the full range of fastener products and services.  Our Cage Code is 58QG4 and our registered name is RL Supply Inc dba MF Supply. 


Buyer’s Guide to Precision Shoulder Screws Refreshed for 2023!

Welcome to our Precision Shoulder Screws Buyer’s Guide Refreshed for 2023! Here are a couple of important details that you must know before setting off to buy Precision Shoulder Screws.

5 Things to Know When Buying Precision Shoulder Screws

Just as Dowel Pins and Retaining Rings are used to locate or hold parts together within a precision assembly or a fixture, so are Precision Shoulder Screws.

Yet shoulder screws are far more versatile. When installed, the unthreaded shoulder acts as a shaft for rotating items such as bearings and bushings, precision spacing, machinery support, and motion guiding. The exacting tolerance of Precision Shoulder Screws makes them ideal for use with other precision components.

They are broadly used across various applications in many industries, including: aerospace, electrical motors, hydraulic equipment, instrumentation, tooling and fixtures, machinery, military and many more.

1. What is a Precision Shoulder Screw? 

Precision Shoulder Screws are generally classified as part of the electronic hardware family. They resemble socket cap screws with an enlarged, unthreaded cylindrical shoulder under the head, and are used to hold parts together within a precision assembly.  Sometimes referred to as “tight tolerance” shoulder screws, they are not governed by any official IFI, ANSI or ASME standard..

Precision shoulder screws are composed of three main parts: the head, the shoulder and the thread.

2. What materials and sizes are available?

Precision Shoulder Screws are readily available off the shelf in type 18-8/303 stainless steel and 416 stainless steel.

Standard stock sizes for the shoulder diameter are Inch from 1/8 to 1/2 and Metric from M4 to M12. The thread class is 2A and the tolerance on the shoulder diameter varies from +.000/-.001 to -.0005 to -.0015 depending upon the manufacturer. Now that’s precise!

316 stainless steel, alloy and other exotic materials, and special diameters and lengths are available in certain sizes and/or for special order and usually involve a lead time.

3. What information do I need for ordering?

The easiest way to order is by manufacturer part number. If you don’t have one, you’ll need to specify shoulder diameter, shoulder length, thread size, material and drive type; for example: 3/16” shoulder diameter x 1” long x 8-32 thread in SS18-8 with a hex-socket drive.

Precision shoulder screws are available in hex socket and slotted drives. Philips, torx and star drives may be available in certain sizes as well.

Typical head styles are a modified fillister with a flat top where the head diameter is about twice the head height and does not need to be specified. Low head fillisters are available in certain sizes.

4. Are there other factors to consider?

YES! One surefire way to save money and shorten delivery time is to cross the OEM brand part on your bill of materials to a functional equivalent.

Popular brands include: Amatom, Cambion, Concord, Globe, HH Smith, Keystone, Lyn-tron, Misumi, Pic Design, RAF, and WM Berg. A comprehensive selection of Precision Shoulder Screws is also offered by McMaster-Carr (tight tolerance series), MSC, and Grainger.

Let’s take the above example of a 3/16” shoulder diameter x 1” long x 8-32 thread in SS18-8 (300 Series) with a hex-socket drive. This part is offered by the seven brands (yes, seven!) listed below under the following part numbers:

  • Grainger 6JY20
  • Lyn-tron SS7431-00
  • McMaster-Carr 94035A208
  • MSC Industrial 67313726
  • Pic Design 4423
  • RAF 6931-SS
  • WM Berg PZ-14-3

You can also find Precision Shoulder Screws under their Mil-Spec numbers, which include MS51575 and MS51576 and are DFARS compliant with full paperwork. The above part is equivalent to a Mil-Spec MS51576-14.

5. What level of certification is required?

Generally, a Certificate of Conformance or a COC is sufficient for your customer. Full certification with material certs and test reports are often available for USA-made and Mil-Spec parts for a fee.

Precision Shoulder Screws at MF Supply

We currently offer:

  • The full range of commercial and mil-spec parts, including parts that are DFARS and ROHS compliant.
  • MS51576 Now available for online purchase!
  • Brand names and generic equivalents.
  • Custom made parts per print in non-standard and exotic materials and finishes.
  • Metric, Inch, and Mil-Spec options & functional equivalents

For more detailed information on Precision Shoulder Screws, visit us at our website or Request a Quote today, and our MF Supply team of sourcing experts can help you find what you need. “Finding the right screw for you” is our tag line after all!


Book a one-on-one consultation with our President, Robin, to discuss how MF Supply can help you solve your Industrial Sourcing, Fastener, and Safety concerns.


MF Supply Work With Us

Six Reasons To Buy From MF Supply

  • Full eCommerce Enabled Website With Technical Manual Available 24/7 – Visit our website and Create a New Account, track online orders, browse our product catalog, check technical specs, subscribe to our blog, or buy online.  We are adding items and improving functionality daily!
  • Same Day Shipping From The USA – Our hardware products are in stock and ship to you directly from our USA based distribution centers. 
  • Functional Equivalents To Expensive Brand Names- We stock and source alternatives to brand name fasteners, reducing long lead times and saving you money.
  • Creatively Solve Problems – We are sourcing experts, offer competitive pricing and specialize in finding hard to find parts and reducing long deliveries.
  • One-Stop Shopping On Certified Hardware – We stock and source a full line of fasteners including Mil-Spec, DFARS compliant and other industrial products.
  • WBE/WOSB Woman Owned Certified Small Business – To meet your diversity & set-aside needs.

MF Supply is a WBE/WOSB certified supply chain partner to business, industry and government.  We are sourcing experts and stocking distributors of Hardware, Precision & Mil-Spec Fasteners and Safety supplies.  For more than 50 years, we have been supplying manufacturers in the electronics, industrial, commercial, aerospace and military markets with the full range of fastener products and services.  Our Cage Code is 58QG4 and our registered name is RL Supply Inc dba MF Supply. 


Over 216 Unique Retaining Rings Now Available for Online Purchase!

MF Supply is a trusted supplier of Retaining Rings to OEMs, Manufacturers and Industry. We now offer a wide selection of over 216 Retaining Rings in stock & available for purchase on our website alone. You’ll find in stock Inch & Metric E-Style (E/SE), External and Internal Retaining Rings in a variety of sizes and materials—such as Steel and Stainless Steel. We offer Brand Names and/or Equivalents to National Catalog and OEM brands including: Anderton, Ellison, IRR, Rotor Clip® and Waldes Truarc®.

Common Uses of Retaining Rings at MF Supply

Retaining Rings are broadly used across various applications in many industries, including: aerospace, drive shafts, electrical motors, hydraulic equipment, instrumentation, lighting assemblies, machinery, nuclear equipment and many more. Retaining Rings are very common in the automotive industry.

Any application with a bore/housing or shaft that requires a shoulder to keep parts in place within an assembly is a candidate for using Retaining Rings.

In-Stock Standoffs and Spacers at MF Supply

At http://www.mfsupply.com, we currently offer over 216 Retaining Rings in E-Style (E/SE), External (used on shafts) and Internal (used for bores) Styles. They also come in many sizes (including Metric sizes), and the general range is from 1/16 to 10″. Materials include Carbon Spring Steel and PH15-7 Stainless Steel. Check out our handy cross reference sheets here.

Below is a list of the Retaining Rings currently available for online purchase at our website.

E-Style Retaining Rings (E/SE)

External Retaining Rings

Internal Retaining Rings

Make ordering the Retaining Rings you require a breeze by visiting our website today, or reach out to us to request a quote for standard or special custom made parts per print.

What the heck are Retaining Rings anyway?

Would you like to learn more about Retaining Rings? Don’t sweat it! Read our recent blog post “Retaining Rings!? What the heck are those?“, from our “What the Heck is that” series to learn more about this category of fasteners.

Can’t find what you’re looking for?

If the OEM brand, size or material you need is not listed above or on our website Request a Quote today, and our MF Supply team of sourcing experts can help find what you need. “Finding the right screw for you” is our tag line after all!


Book a one-on-one consultation with our President, Robin, to discuss how MF Supply can help you solve your Industrial Sourcing, Fastener, and Safety concerns.


MF Supply Work With Us

Six Reasons To Buy From MF Supply

  • Full eCommerce Enabled Website With Technical Manual Available 24/7 – Visit our website and Create a New Account, track online orders, browse our product catalog, check technical specs, subscribe to our blog, or buy online.  We are adding items and improving functionality daily!
  • Same Day Shipping From The USA – Our hardware products are in stock and ship to you directly from our USA based distribution centers. 
  • Functional Equivalents To Expensive Brand Names- We stock and source alternatives to brand name fasteners, reducing long lead times and saving you money.
  • Creatively Solve Problems – We are sourcing experts, offer competitive pricing and specialize in finding hard to find parts and reducing long deliveries.
  • One-Stop Shopping On Certified Hardware – We stock and source a full line of fasteners including Mil-Spec, DFARS compliant and other industrial products.
  • WBE/WOSB Woman Owned Certified Small Business – To meet your diversity & set-aside needs.

MF Supply is a WBE/WOSB certified supply chain partner to business, industry and government.  We are sourcing experts and stocking distributors of Hardware, Precision & Mil-Spec Fasteners and Safety supplies.  For more than 50 years, we have been supplying manufacturers in the electronics, industrial, commercial, aerospace and military markets with the full range of fastener products and services.  Our Cage Code is 58QG4 and our registered name is RL Supply Inc dba MF Supply. 


Retaining Rings!? What the heck are those?

Welcome back to our “what the heck is that” series, refreshed for 2023, where we discuss some of the unique fasteners and electronic hardware that manufacturers use in the design and assembly of their products. Today, we will re-introduce you to the Retaining Ring!

What is a Retaining Ring?

Retaining Rings are yet another way to position, locate and retain parts within an assembly. Shaped like an open ring and made of metal, Retaining Rings can be coiled from wire, stamped or laser cut. They come in a variety of styles and materials, each solving a unique fastening problem.

Generally, Retaining Rings work together with a bore or a shaft by snapping into a groove or being pushed into place to create a high strength shoulder to retain parts.

AKA – Also known as…..

The Retaining Ring is a funny little guy and answers to a bunch of different names – some of Retaining Ring’s favorite aliases are: snap rings, wire rings, circlips, retainer clips, spiral rings, wire clips, c-rings, e-rings, grip rings, klip rings and push-on rings.

Who uses Retaining Rings?

Any application with a bore/housing or shaft that requires a shoulder to keep parts in place within an assembly is a candidate for using Retaining Rings.

Retaining Rings are broadly used across various applications in many industries, including: aerospace, drive shafts, electrical motors, hydraulic equipment, instrumentation, lighting assemblies, machinery, nuclear equipment and many more. Retaining Rings are very common in the automotive industry.

Why use a Retaining Ring vs. a screw or a bolt?

When a shaft or bore design that includes assembled components needs a shoulder, it can be costly to machine the shoulder, mate threaded components and fasteners together and drill and coordinate threaded holes and access holes to fasten the assembly. Retaining Rings can serve as a cost effective and time saving alternative. In addition to cost, Retaining Rings offer 2 special benefits a) they can be more resilient than screw assemblies in high vibration environments, b) they are made from less material, hence they are lighter, cleaner, gentler on the environment (aka Green!).

What styles are available?

Retaining Rings come in a variety of styles and materials. The most popular styles are: External (used on shafts), Internal (used for bores) and E-Style (radially assembled). The most popular materials are Carbon Spring Steel, PH15-7 Stainless Steel and Beryllium Copper. The most common finishes for Carbon Steel Rings are Phosphate, Zinc Clear and Zinc Yellow.

Are there other factors to consider?

  • As discussed, Retaining Rings are often referred to by their brand names, which can often be substituted by generic equivalents. Popular brands include: Anderton, Arcon, Rotor Clip, Waldes/Truarc. We can supply the brand name or generic alternatives.
  • Retaining Rings often show up under their Mil-spec numbers, which can be crossed to commercial equivalents. Some common Mil-spec series for Retaining Rings include: MS16624, MS16625, MS16626, MS16627, MS16628, MS16629, MS16630, MS16631, MS16632, MS16633, MS3215, MS3217 and MS90707.
  • Sizes available vary based on the style. The general range is from 1/16 to 10″. Metric sizes are also available.

Retaining Rings at MF Supply

We currently offer:

For more detailed information on Retaining Rings, visit us at our website or Request a Quote today, and our MF Supply team of sourcing experts can help you find what you need. “Finding the right screw for you” is our tag line after all!


Book a one-on-one consultation with our President, Robin, to discuss how MF Supply can help you solve your Industrial Sourcing, Fastener, and Safety concerns.


MF Supply Work With Us

Six Reasons To Buy From MF Supply

  • Full eCommerce Enabled Website With Technical Manual Available 24/7 – Visit our website and Create a New Account, track online orders, browse our product catalog, check technical specs, subscribe to our blog, or buy online.  We are adding items and improving functionality daily!
  • Same Day Shipping From The USA – Our hardware products are in stock and ship to you directly from our USA based distribution centers. 
  • Functional Equivalents To Expensive Brand Names- We stock and source alternatives to brand name fasteners, reducing long lead times and saving you money.
  • Creatively Solve Problems – We are sourcing experts, offer competitive pricing and specialize in finding hard to find parts and reducing long deliveries.
  • One-Stop Shopping On Certified Hardware – We stock and source a full line of fasteners including Mil-Spec, DFARS compliant and other industrial products.
  • WBE/WOSB Woman Owned Certified Small Business – To meet your diversity & set-aside needs.

MF Supply is a WBE/WOSB certified supply chain partner to business, industry and government.  We are sourcing experts and stocking distributors of Hardware, Precision & Mil-Spec Fasteners and Safety supplies.  For more than 50 years, we have been supplying manufacturers in the electronics, industrial, commercial, aerospace and military markets with the full range of fastener products and services.  Our Cage Code is 58QG4 and our registered name is RL Supply Inc dba MF Supply.