We recently published an article on what a helicoil is, so we thought it would be helpful to give a brief overview of the most common helicoils. There are a variety of helicoils available for purchase, but our guide will focus on inserts pertaining to metal.
Stainless Steel Helical Inserts
These are your most standard type of insert found on the market. Once installed, the coils expand to securely anchor the insert inside of the tapped hole. All helicoils require a special installation tool and the prong inside of the helicoil must be broken off afterwards.
A grade of helicoils within the stainless steel family are Nitronic 60 helicoils. This type of helicoil is commonly used to prevent screws from binding or sticking without any coating or lubricant that could contaminate an environment.
Lubricated Stainless Steel Helical Inserts
Lubricated helicoils are the exact same as standard helicoils mentioned above, but they have a dry film that helps keep screws from sticking or binding during use. This type of helicoil also requires special manufacturing and installation tools, and the prongs inside of the insert must be removed before use.
Nickel Alloy and Titanium Helical Inserts
Nickel alloys inserts are more resistant to acids and salt water than stainless steel inserts. Titanium inserts posses the highest strength rating and the best corrosion resistant properties out of all of the helicoils available. However, these premium features come at a significant price increase compared to stainless steel inserts.
Screw Locking Helical Inserts
Screw Locking helicoils have all of the same characteristics as standard helicoils, but they allow for screws to be locked into place. This is accomplished through a series of polygon shaped coils in the center of the insert. Screws inserted into the helicoil can be taken out with relative ease, but when tightened they will not come out unless they experience extreme conditions.
An alternative to this style of helicoil inserts is a technology developed by Stanley called spiralock. Spiralock threads don’t require an insert and they have tapering threads that allow screws to tighten with each turn. These threads are difficult to machine, but they do achieve the same screw locking result.
Helical Inserts without Prong
These inserts are exactly like the standard helical inserts, but they already have the prongs or tangs removed. This eliminates a step in having to break them after installing them. It is a simple luxury that can be nice when you are installing hundreds of helicoils.