Heli-coil® vs. Keensert®
AKA Helical Wire Inserts & Key-Locking Inserts
What Are They?
Helical Wire Inserts, also known as "Heli-coils" are precision-formed continuous wire coils that provide permanent, wear-resistant threads which exceed the strength of the parent material. Often underestimated, the popular misconception is that Helical wire inserts are intended solely for thread repair when in fact they have many other uses. Helical inserts are commonly referred to as “Heli-Coils” which is a registered trademark of Emhart® Teknologies, Inc.
The Key-Locking Threaded Insert, also known as the Keensert,  is a solid bushing style insert that is threaded on both the inside and the outside and has wedges or “keys” attached to the top of the insert. They are commonly used in high torque and high temperature situations, and in applications where fasteners may be repeatedly removed and reassembled. Key-locking inserts are often referred to as Keenserts® which is a registered trademark of Huck Patents, Inc. & Keysert® a registered trademark of Alcoa Fastening Systems.
Key Differences
  • Strength: A key-locking insert is much stronger than a helical insert, particularly in high temperature/torque environments.
  • Easy Installation: A key-locking insert is easier to install than a helical wire insert.
  • Price: A Helical wire insert is much less expensive than a key-locking insert.
Which One Is Right For You?
Here is some direction on how to select the correct threaded insert.

In heavy wear, high vibration and high heat situations where saving space is not a concern and hole depth is limited, Key-Locking Inserts are the best bet.

When reducing costs and minimizing space are priorities, Helical Wire Inserts are the way to go. They are particularly useful for creating permanent strong threads in softer materials such as aluminum, titanium and magnesium alloys, and are best suited to lower heat and lower torque environments.
To learn more about our inserts visit our blog, or email your questions to sales@mfsupply.com
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