Window Lock Security: Grub Screw Mechanism Explained

A grub screw, also known as a set-screw, is a type of bolt used to fasten objects together without the need for a nut. This makes them highly versatile, as they can be used in situations where a compact and inconspicuous fixing is required. Grub screws are commonly used in mechanics and engineering to secure metal surfaces that rub together, as well as in architectural ironmongery to attach door handles and knobs to spindle shafts. They are available in various diameters and lengths and can be easily fitted using an Allen key. While they are typically headless, they can also be found with cone or cup points. In the context of window locks, grub screws can be used to secure sliding or moving components, making them a useful tool for locking mechanisms.

How to grub screw a lock

Grub screws are used to fasten objects together without the need for a nut. They are often used in window locks, door handles, hinges, and tilt and turn window parts.

• When starting, it is recommended to use a 3.5mm tap to begin the thread, and then a 4mm tap for the grub screw.
• Alternate the chambers that you are tapping.
• Use a grub screw that is shorter than what you think you need. Cut some threads, insert the grub screw, turn the lock around, and drop the spring in.
• Use the spring to gauge how deep you need to keep tapping the chamber. The spring should sit slightly above or at the shear line.
• If you use a 4mm tap, be careful not to cut into the wall of the next chamber.
• Ensure that the grub screw sits below the surface of the bible when you are done.
• Use sandpaper to knock off any burs from tapping on the top of the chambers.
• To make it easier to knock out the plugs, you can drill a hole all the way through the cap with a drill bit. This allows the cap to flex and slide out more easily.

It is important to note that grub screws come in various sizes, so you may need to measure the length and point required, as well as estimate the thread size. They are typically tightened with an Allen key.

Using grub screws for window frame keeps

Grub screws are an excellent option for window frame keeps due to their versatility and unobtrusiveness. They can be easily fitted using an Allen key and provide a strong grip for window frames.

Grub screws are typically used to fasten one object to another without the need for a nut. This characteristic is advantageous for window frame keeps as it allows for a more compact and inconspicuous fixing. The small size of grub screws means they can be used in tight spaces without causing obstruction, making them ideal for window frame applications.

When selecting a grub screw for a window frame keep, it is important to consider the diameter and length that will best suit your specific window frame. Common diameters for grub screws start as small as 1mm for precision applications and can go up to 10mm or more for heavier-duty purposes. The length of grub screws can vary from just a few millimetres to several centimetres, depending on the intended use.

To install a grub screw for a window frame keep, follow these steps:

• Measure the diameter and length required for your specific window frame application.
• Select a grub screw with the appropriate dimensions. Consider using a cup point grub screw for flat-faced spindles or a cone point grub screw for slotted spindles.
• Use an Allen key to tighten the grub screw and secure the window frame in place.

By following these steps and choosing the right grub screw for your window frame keeps, you can ensure a strong and secure grip that will keep your windows in place.

Types of grub screws: cone point and cup point

Grub screws are used to fasten objects together without the need for a nut, making them ideal for compact and inconspicuous fixings. They come in a variety of types, including cone point and cup point.

Cone Point Grub Screws

Cone point grub screws are ideal for use with a slotted spindle, where the point locates in the slot, putting pressure on the slot to ensure a tight fit for the spindle in the handle. They are available in different thread sizes and lengths, with common diameters ranging from 1mm or less for precision applications to 10mm or more for heavier-duty use.

Cup Point Grub Screws

Cup point grub screws feature a concave cup point that allows them to fit closely against a rounded surface, such as a motor shaft. They are designed to hold components in place with pressure from the tip rather than fastening against the threads. This unique cup point tip provides better clamping compared to other set screws and offers a longer lifespan. Cup point grub screws are available in a wide range of materials, including stainless steel, aluminium, brass, and phosphor bronze. They come in various diameters, from 1.6mm to 20mm, and lengths ranging from 2mm to 120mm.

Using grub screws to fasten steering shafts

Grub screws are used to fasten steering shafts inside UV collars. They are typically used to fasten one object to another without the need for a nut, making them ideal for compact and inconspicuous fixings.

When using grub screws to fasten steering shafts, it is important to consider the size and type of screw required. Grub screws come in a variety of sizes, ranging from very small diameters of a couple of millimetres to larger sizes similar to standard screws. The size of the grub screw will depend on the specific application and the strength required for the connection.

In addition to size, there are several types of grub screws available, each with a unique point design. For example, cup point grub screws are ideal for use with flat-faced spindles, while cone point grub screws are better suited for slotted spindles. The choice of grub screw type will depend on the materials being used and the desired level of force or pressure.

To fasten steering shafts, it is recommended to use a grub screw that is shorter than what is initially estimated. This will ensure that the screw sits below the surface when it is installed. It is also important to consider the drive type required to seat the grub screw, such as hex sockets (Allen keys) or star sockets (Torx).

When installing grub screws, it is crucial to follow safety guidelines and regulations, especially when working with critical fasteners in the steering system. For example, Loctite is not considered a permitted securing method for critical fasteners in steering shafts. Instead, consider using a bolt with a head that can be drilled for locking wire or adding a custom tab washer to positively lock the grub screw in place.

Advantages of headless grub screws

Grub screws, also known as set screws, are typically used to fasten one object to another without the need for a nut. This makes them highly versatile, as they can be used in situations where a compact and unobtrusive fixing is required. They are often used in mechanical systems where metal surfaces rub together and cannot be obstructed by screw or bolt heads, such as in pulleys and gears. They are also used where recessed screws are necessary for aesthetic or security reasons, such as in wall joints or public restroom dividers.

The development of headless grub screws was driven by a major early 20th-century campaign for better industrial safety. The headless design removes the risk of workers' clothing or fingers catching on exposed rotating screw heads. This design is also advantageous for aesthetic reasons, as it results in a smoother and less obtrusive appearance.

Headless grub screws offer several benefits over traditional screws or bolts. One key advantage is their corrosion resistance, as the entire length of the screw is typically encased in the material it is fastening, with no exposed edges. This also allows for the screw to be tightened with more torque, as the surrounding material reinforces the head during the tightening process. Additionally, the headless design can make it more difficult to unscrew the screw, providing added security.

The use of headless grub screws also allows for a stronger grip and more secure fixing. The lack of a head means there is no protruding sharp edge that can catch on fingers or clothing. Furthermore, the headless design facilitates the application of higher torque during fitting, resulting in a tighter screw. This is due to the use of internal socket drives such as hexagonal Allen (hex) sockets or Torx sockets, which can withstand greater torque before the head becomes malformed.

Frequently asked questions