Shoulder screws are essential components used in many industries from aerospace and defense to medical devices and consumer goods. Their unique design allows them to maintain alignment, while providing reliable connections. This guide will help you understand the different types of shoulder screws, how to choose the right one for your application, and where they're commonly used.
What is a Shoulder Screw?
Unlike standard screws or bolts, shoulder screws feature an unthreaded cylindrical portion immediately below the head. This part is known as, you guessed it, the shoulder! This section, also known as the barrel, is precision-machined to extremely tight tolerances. This makes it suitable for use as a bearing surface or pivot point. It’s interesting to note that the shoulder diameter is always larger than the major diameter of the threads. Further, the threaded portion is often shorter than the shoulder length and is used to secure the screw in place.
Types of Shoulder Screws
Shoulder screws are classified by their head types. Three of the most common are Phillips, slotted, and socket head. The Phillips head features a cross-shaped recess and is widely used in industrial settings due to their ease of use with automated tools. Slotted head has a single straight recess and is common in less demanding applications. Socket (or hex) head has a hexagonal recess and is preferred in high-torque applications where maximum strength is required.
The ideal head type depends on several factors such as strength requirements, environment, installation method, and user expertise.
Installation Method – how the screw will be driven is a key factor in deciding ideal head type. For instance, for certain applications, Phillips head screws may be favored for many reasons. They are easier for automated machinery, since the cross shape guides the driver into place. The shape also reduces slippage, while allowing for better torque transfer. These factors add up to increased speed and efficiency, which are vital to high-volume manufacturing. The same could be said for hex head shoulder screws.
Conversely, slotted heads are better for consumer applications as they are favored by end users due to their simplicity.
User expertise – as mentioned previously, for consumer products, slotted heads are generally preferable due to their simplicity.
Materials for Shoulder Screws
Material choice also plays a crucial role in shoulder screw selection. The most common options are 303 and 416 stainless steel, while other applications call for custom materials. Let’s take a closer look at these options:
303 Stainless Steel - offers excellent corrosion resistance with moderate strength.
416 Stainless Steel – is heat treated and therefore provides higher strength but with reduced corrosion resistance as compared to 303.
Custom Materials - for applications with specialized requirements, custom materials can be explored. Manufacturers, including PIC Design, can provide alternatives based on specific needs and operating conditions such as exposure to moisture, salinity, or extreme temperatures.
Common Shoulder Screw Applications
Shoulder screws are designed to bear shear loads, making them ideal for applications involving rotation or lateral forces. They are engineered to provide a fixed axis of rotation, precise spacing, or a bearing surface in various mechanical assemblies. They excel in applications where standard fasteners would be imprecise or prone to premature wear.
The precise barrel on shoulder screws makes them ideal for creating smooth, rotating connections in pivot points. The shoulder acts as a bearing surface for rotating components. Shoulder screws also ensure exact positioning of components. This makes them ideal for uses requiring alignment, such as precision electronics found in aerospace. They are found in medical components, manufacturing equipment and robotics as well, for the same reason.
Conclusion
Shoulder screws are versatile fasteners that play a critical role in many precision applications. By understanding the different configurations and materials available and matching them to your application’s requirements, you can ensure optimal performance and longevity of your mechanical assemblies. Whether you're working on a complex component or a simple pivoting mechanism, the right shoulder screw can make all the difference in the success of your product.
Built-to-print Parts
We are experts in custom parts
manufacturing
HOW CAN WE HELP YOU?
Our goal at PIC is to provide exceptional customer service. We can assist you online, or you may reach us by email or phone. Our experienced customer service representatives can provide answers to: placing an order, requesting a quote, price and delivery, order status, and product cross references.
Contact us today and allow PIC to Keep You on Target!
-
8:00 AM - 6:00 PM (ET), Mon-Thurs
8:00 AM - 5:00 PM (ET), Fri - 86 Benson Rd., Middlebury,
CT 06762 - 203-758-8272
+1 800-243-6125 - 203-758-8271