Hex Bolt vs. Hex Cap Screw: What's the Difference?
Hex bolts and hex cap screws look similar, but differences in their design and dimensional specifications can affect which fastener your application requires. Both have six-sided heads, but a hex cap screw typically has a washer face beneath the head and a chamfered point, while a hex bolt does not require these features under ASME B18.2.1.
Understanding the differences between hex bolts vs. hex cap screws can help you identify the correct fastener, verify specifications, and avoid ordering the wrong part.
What Is a Hex Bolt?
A hex bolt is an externally threaded fastener with a six-sided head designed to be tightened with a wrench or socket. It is commonly used with a nut to secure two or more components together.
Hex bolts are widely used in construction, equipment assembly, and industrial maintenance. Depending on the product specification, they may have a plain bearing surface beneath the head and an unchamfered point.
When selecting a hex bolt, verify its diameter, length, thread specifications, material grade, and finish to ensure it meets your application's requirements.
What Is a Hex Cap Screw?
A hex cap screw also has a six-sided head, but it is manufactured to specific dimensional requirements. Under ASME B18.2.1, hex cap screws feature a defined washer face beneath the head and a chamfered point.
Hex cap screws are commonly installed into tapped holes, where internal threads in the receiving component secure the fastener. They may also be used with nuts in appropriate assemblies.
These fasteners are frequently used in machinery, equipment, and precision assemblies where specified dimensions and fit are important.
Hex Bolt vs. Hex Cap Screw: Key Differences
Feature | Hex Bolt | Hex Cap Screw |
Head shape | Six-sided | Six-sided |
Washer face | Not required by the product standard | Defined washer face |
Point | Does not have to be chamfered | Chamfered point |
Dimensional requirements | Different tolerances for certain features | More closely controlled dimensions for certain features |
Common installation | Often secured with a nut | Often installed in a tapped hole or used with a nut |
These are general distinctions for inch-series fasteners covered by ASME B18.2.1. Always consult the applicable standard and product specifications when identifying a fastener.
Can You Use a Hex Bolt and Hex Cap Screw Interchangeably?
Not automatically. Although the two fasteners can look similar and may be suitable for some of the same assemblies, their dimensions, material grades, thread specifications, and applicable standards must meet the requirements of the application.
Before substituting one for the other, check the engineering drawing or equipment manufacturer's requirements. Confirm the diameter, thread pitch, length, material grade, coating, and any required dimensional tolerances.
If the original specification calls for a particular fastener type, do not assume that a similar-looking product is an acceptable replacement.
How to Choose the Right Fastener
When sourcing a hex bolt or hex cap screw, confirm the following details:
Size: Verify the required diameter and length.
Threads: Check the thread pitch, thread series, and required thread length.
Material and grade: Select the specified strength and corrosion-resistance characteristics.
Finish: Confirm whether the application requires plain steel, zinc plating, hot-dip galvanizing, or another finish.
Standard: Match the applicable dimensional and material specifications.
Having these details available makes it easier to identify the right product and reduce ordering errors.
Need Help Finding the Right Fastener?
Choosing between a hex bolt and a hex cap screw starts with understanding the specifications your application requires. Florida Industrial Solutions helps businesses source industrial fasteners and hardware for their operational needs.
Browse our fastener catalog to explore available products. Need help identifying a specific part? Contact our team or request a quote.
Technical Reference
Always confirm the applicable fastener standard and engineering requirements before selecting a replacement.
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