Everything you need to know about conical-head grub screws (Allen screws) for door handles

A detailed article explaining what a "grub screw" and an "Allen screw" are when it comes to fitting door handles.

When installing door handles, it is essential to use the right components, such as conical-head grub screws, also known as Allen screws. These screws play a crucial role in securing door handles by ensuring a strong and durable grip. But what exactly is a conical-head grub screw (Allen screw)? Through this article, we will explore in detail what a grub screw is, how it works, and give you some expert tips for a successful installation of your door handles.

1. Conical-head Allen screw (Grub Screw)

Grub screws are specially designed to hold door handles firmly onto a square spindle passing through the door. These grub screws feature a conical tip and an Allen key socket. When you tighten the screw using a rotating motion, the square spindle expands, thus immobilising the handle securely.

These grub screws are made from brass, a robust material, ensuring their longevity. The "head" of the screw can also be made from galvanised steel.

An important feature of these grub screws is their conical head. This design allows for precise and stable fixing of door handles, preventing any unwanted movement. Some grub screws also feature a countersunk head or a round head, offering different options for aesthetics and function.

It is common to find grub screws in different sizes, such as M6 and M3, to suit various applications. The choice of size depends on the type of door handle you are installing.

The standard mounting kit for a door handle generally contains two types of screws:

• One M6 Allen screw per handle, used to secure the handle lever onto a split square spindle.
• One small M2/M3 Allen screw, designed to secure the handle plate onto the metal adapter.

Expert Tip: When using grub screws, make sure to tighten them firmly to avoid any play in the door handle. However, do not overtighten, as this could damage the square spindle or the handle itself.

Furthermore, if you are installing a door handle on a wooden surface, it is recommended to use appropriate wood screws for a robust fixing. These screws are specially designed for wood and ensure a strong grip.

Here is a comparison table of Allen grub screw dimensions, including different sizes such as Allen M3, Allen M4, Allen M5, and Allen M6.

The grub screw is sometimes called a "bookbinding screw", "fixing screw", "fastening screw", or "door handle screw". An example of installing a handle with Allen grub screws is illustrated below.

Here is the dimensions table:

2. How to install an Allen grub screw in a square spindle

The correct installation of an Allen screw is essential to ensure the door handle remains securely in place. The screw must be inserted into the square spindle in such a way that it expands inside the handle. This creates an Archimedean screw or worm screw effect, which effectively locks the handle onto the door.

The use of an Allen key is recommended to ensure precise tightening of the screw in the square spindle. Make sure the screw is properly aligned before beginning to tighten. Once tightened, the handle should be firmly secured with no play.

By putting these expert tips into practice and making the right choice among conical-head grub screws (Allen screws) and the necessary door spare parts, you ensure a hassle-free installation and maintain the long-term stability and security of your door handles.

So, don't wait any longer to start your renovation work! Our Millahandles shop offers you a magnificent catalogue of handles, parts and accessories.