Set screws

Experience our large range of set screws

Bossard is a leading supplier of set screws and other fasteners servicing the industrial and manufacturing sectors. We have hundreds of thousands of items on stock and benefit from a vast global supply network, making us an ideal partner for your business.

At Bossard, you'll find set screws of all sizes and types in steel, stainless steel, polyamide, and brass in our standard range.

 

What is a set screw?

A set screw is a screw without a head, typically fully threaded. Set screws are also known as grub screws.

The end/point of a set screw can be flat, a cone point, a dog point, or a cup point. The point of the set screw is included when measuring its length.

A set screw has an internal drive. This is typically a straight slot, a hexagon socket or a hexalobular socket.

In the Bossard E-shop, set screws are available in steel with various surface treatments, along with stainless steel (A2 and A4), brass and polyamide. The optimal material for the set screw depends on the application and environment in which it is installed. You can read more about materials further down the page.

 

Where are set screws used?

Set screws are used to prevent movement between two parts. When the set screw is installed, its end/point tightens against another component and holds it in the desired position.

A common example is that set screws are used to install door handles - this is perhaps what set screws are best known for. However, set screws are used in many different applications beyond this, from wheel bearings and axles to toilet roll holders and planers.

Set screws can only be used for smaller loads, as the retention is solely due to the friction between the end/point of the set screw and the object it is tightened against. And because the drive is small enough to fit inside the screw, the screw can only be tightened with a low torque.

 

The point/end of the set screw

 

• Flat point: Set screws with a flat point have an end that is cut perpendicularly and is of course flat. This type of set screw is used when the screw needs to tighten against a completely flat surface.
• Cone point: Set screws with a cone point have a tapered end ending in a single point and are used when the screw needs to tighten against a round object where a flat point cannot be used. The point will not rotate the object with it when tightened as it has such a small contact surface.
• Cup point: Set screws with a cup point have a recess in the center. This type of screw has a small contact surface, just like a set screw with a cone point, but the difference here is that all the load is not concentrated at one point, but on the edge of the recess.
• Dog point: Dog point set screws have a small, unthreaded tap at the end that fits into a hole in the object it's tightened against. This allows the object to rotate but still maintain its position in the structure.

 

Stainless steel set screws

If the set screw is installed in a location where it is exposed to an outdoor climate, it is a good idea to choose a stainless steel set screw. Stainless steel screws are, of course, made from stainless steel, which has favorable corrosion-resistant properties.

Corrosion resistance is increased in stainless steel by adding certain elements that make the fasteners less likely to corrode in aggressive environments. These elements include chromium, nickel, and molybdenum, among others.

A2 stainless set screws are suitable for outdoor use and for use in humid environments. However, an A2 stainless set screw is not suitable for applications where they are exposed to acid, for instance from acidic wood or food, nor should they be used near or in seawater.

A4 stainless steel set screws, on the other hand, are suitable for use in or near seawater, as this type of steel has a superior corrosion resistance. A4 screws are also acid-resistant, so they can be used in applications where they are exposed to acid, for instance in machines for food processing.

Bear in mind, however, that no set screws are in reality corrosion-proof - rather, they are corrosion-resistant. All screws will corrode over time; however, stainless steel screws corrode at a significantly lower rate than standard steel screws.

 

Brass and polyamide set screws

Brass and polyamide are alternative materials to set screws in steel, chosen for their properties that can provide a practical advantage in the manufacturing of a product.

Brass is a non-ferrous metal with a noble visual appearance. Brass set screws have a fair corrosion resistance, are non-magnetic and have good electrical conductivity. Brass is also a softer material than steel, which reduces the risk of damaging the component the screw is tightened against during installation.

Polyamide is a synthetic material. It is also called nylon. Polyamide set screws are electrically insulating and lightweight, so they are often used when these properties are an advantage. Like brass, polyamide is softer than steel, so using polyamide set screws also reduces the risk of damaging the component they are tightening against.

 

Surface treatments for steel set screws

Set screws and other steel fasteners are available uncoated or with a surface treatment that increases corrosion resistance and makes them less prone to rusting.

In the Bossard E-shop, you'll find zinc plated and zinc flake coated set screws as well as uncoated blackened steel set screws in our standard range.

• Uncoated/black steel: Uncoated/black steel set screws have not been given any kind of surface treatment, at the most a thin coating of oil to protect them during transportation.
• Zinc electroplated steel: Zinc plating is the process of adding a thin layer of zinc to the surface of the set screws - a process performed in rotating barrels. The thin layer of zinc increases the screw's resistance to rust/corrosion to a certain degree, but not enough for outdoor applications.
• Zinc flake coated: Zinc flake coating is a process that significantly increases the corrosion resistance of the fastener. It is done by immersing the fastener in a water bath solution containing zinc and aluminum flakes.

 

What type of set screw should you choose?

Do you need help choosing the right set screw for your product? Let our fastening experts help you with your choice.

With our service "Expert Design", our engineers who have many years of experience with fasteners and fastening technology will help you choose the optimal screw for your application. Our experts will be able to guide you through the various options to ensure a high-quality product with the lowest possible production costs.