What Is A Self Tapping Insert?
Self Tapping Inserts are a versatile type of component used to add machine threads into a plain, untapped hole, creating a secure anchor.
These threaded fasteners are commonly used as a cost effective solution to enable machine screws to be fastened into a broad range of materials within the automotive, aviation and furniture industries.
What Are Self Tapping Inserts Used For?
A Self Tapping Insert is used to create stronger threads than would otherwise be produced directly in the base material. For example, in the aviation industry, this type of fastener can be inserted into aluminium parts to provide a stronger fixing point.
For the same reason, in some machine shops it is standard practice to use Threaded Inserts in cast iron parts, which is known for being brittle and prone to fracturing.
In the furniture industry, Self Tapping Inserts are used to provide threads in manufactured materials such as chipboard, which would have low strength when used with a standard thread.
Common Mistakes When Installing Self Tapping Inserts
Self Tapping Inserts are installed by a range of methods, from Screwdrivers, to Hexagon Keys and even in rare cases, with a socket.
Accu’s stainless steel Self Tapping Inserts are designed to be installed with a specialist tool, however if necessary they can also be installed using a suitable fastener and nut, as detailed in the image above. Whilst the nut is not strictly required, it will aid in removing the fastener post installation.
As illustrated in the image, the most common mistake encountered when installing a Self Tapping Insert is to use a Slotted Screwdriver to attempt to fasten the component upside down, as opposed to the correct orientation, with the tapered self tapping thread driving directly into the housing material.
Are Threaded Inserts Stronger Than Screws?
Threaded Inserts are commonly used to provide stronger female threads in a part. This creates a more secure fixing in materials that are of a lower tensile strength than the fastener, as discussed above.
As the Insert effectively creates an external thread with a larger diameter, this results in a pull-out resistance that is greater than that of the smaller diameter screw, if it were fastened directly into the substrate without an insert.
This means that the insert is often stronger than the fastener, except in the case of our Socket Drive Inserts which, owing to their zinc alloy construction, are weaker than typical machine screws.
However they are more than strong enough for their intended application as they are designed for use in materials which are significantly weaker than both the screw and the insert.
In some cases it is not necessary to use threaded inserts, for example within thin sheet metals and some non-ferrous materials where the added strength is not required.
In these instances, Self Tapping Screws are a more economical alternative, requiring less work to install, reducing the overall part count and as a result the cost to the end user.
You can learn more about Self Tapping Screws and how they can be used in a range of materials, including woods, plastics and metals, in our article comparing them with Self Drilling Screws.
What Types Of Self Tapping Inserts Do Accu Sell?
Accu stocks a standard range of two different types of Self Tapping Inserts.
Our Stainless Self Tapping Inserts can be used in metallic materials, primarily used within fastening applications involving non-ferrous metals. However, they are also suitable for use with other material types including polymers, composites and wood.
In certain circumstances these components can also be used as thread reducers, providing the external thread pitch matches the pitch of the female threaded part.
The Cone Shaped Self Tapping Inserts are specifically designed for use in wood, with their coarse thread allowing for a faster installation and better grip in manufactured boards.
Conical shaped inserts are often used to install feet, handles and other machine threaded items in wooden construction.
Shop Self Tapping Inserts
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How To Install Different Types Of Self Tapping Insert
These fasteners can be installed by a range of methods depending on the type of insert and the application. Socket Drive Inserts can be installed with a suitable hex screwdriver or allen key, into a pre-drilled pilot hole.
Accu’s Stainless Steel Threaded Inserts are designed to be installed with a specialist driver tool. However if only a few inserts are required, they can be installed with a standard threaded fastener, washer and nut. The components are arranged and installed by driving the fastener as detailed in the image.
Can You Reuse Threaded Inserts?
Threaded Inserts are not designed to be reused, however depending on the type of insert and application they can technically be removed with a driver tool and reinserted.
It is worth noting that this is not recommended and may weaken the threads created by the insert.
Recommended Pilot Hole Sizes For Threaded Inserts
The following table shows the recommended pilot hole size for fastening Socket Drive Inserts into wood.
Please note: This article is intended to provide guidance only and, as a result of various environmental factors, fastening applications may differ. Accu will not be held responsible for any failure that may occur from the use of this guide.