You need different types of screws for different situations. Sometimes, regular screws won’t do. What is a set screw?
A set screw is a screw without a head. This is for applications where you cannot have a head protruding out after two materials are joined together. You can use set screws to attach gears to shafts or pulleys to gears.
With the right screws, you can make two pieces of wood move smoothly around a durable joint.
What is a Set Screw?
Set screws are threaded from top to bottom. They work in a different way from regular screws and are used for different purposes.
Set screws are for situations where you need to secure two things together without anything protruding. If you use a regular screw, a head will protrude out of one of the two things you attach together.
However, with a set screw, there is no protruding head. This makes it possible to build some things that you could not build the same way otherwise. While they are not nearly as commonly used as regular screws, they have many applications.
How Do Set Screws Work?
Set screws work by compressional force and not only by the thread. When you use an Allen wrench or a special tool to fasten the screw, it pushes the two materials together and creates a clamping force.
What Do People Build With Set Screws?
Many mechanical things contain set screws. A set screw is often the best way to put a gear on the end of a shaft. People also use set screws to attach collars or pulleys to shafts.
Doors and door knobs include set screws. They are used in joinery and ironmongery.
Types of Set Screws
There are different types of set screws with different points. Some are designed for more delicate materials.
Dog Point Type
Dog point set screws have a tubular point that can go into a machined groove. You can use them instead of dowel pins. With dog point set screws, the shaft can spin freely while the spindle remains in place.
Half Dog Type
These are the same as dog point screws but with a shorter tip.
Cup Point Type
These screws have cupped points that cut into the material to hold everything in place securely. They are the most popular type.
Cone Point Type
Cone point screws have a sharp, penetrating point to permanently attach two things together.
Nylon Point Type
Nylon points are designed not to damage more delicate materials. They are similar to dog point screws but the point is made of nylon, not metal.
Oval Point Type
Oval points have an oval tip. They are one of the best choices if you want a screw you can adjust repeatedly without damaging the material you are working with.
Knurled Cup Point Type
These screws are used in applications where there is a lot of vibration. These cup screws have a serrated ridge on the cup, which digs into the surface and prevents the screw from slipping out when there is a lot of vibration.
Flat Point Type
Flat point set screws are designed to minimize damage to the material. They are useful if you will presumably need to adjust the screw in the future.
Different Materials for Set Screws
If you need strength, go with stainless steel, alloy steel, or plastic set screws instead of brass set screws. Plastic and stainless steel are lighter than the other two materials. Plastic, stainless steel, alloy steel, and brass are all corrosion-resistant.
Set Screws for Different Purposes
Different shapes of screws are better for different purposes. Use the right type of set screw for the right situation, such as:
- For a permanent hold, do not use an oval or flat screw.
- Use a cone screw for a high-compression hold.
- Oval and flat screws can be reused without damaging the threads.
- Cone screws can be used as hangar points.
- Cup screws, cone screws, cone screws, and knurled cup screws work on both hard and soft materials.
- Nylon and oval screws work on many different angles.
- Dog screws and half-dog screws fit into holes easily.
- Half dog and oval screws fit into grooves.
- Cone and flat screws work as adjusting screws.
Set Screws Compared to Bolts
Set screws are similar to bolts in the sense that they go into previously existing holes. With regular screws, you usually drill them through a surface to create a hole. You are not likely to drive a set screw or a bolt into a material.
The difference is that a bolt has a protruding head. This makes bolts unsuitable in situations where the screw or bolt needs to be flush with the surface.
Set Screws Compared to Grub Screws
Arguably, set screws are the same as grub screws, but there could be certain differences. People do not agree on how to define the difference between the two.
Arguably, a set screw counts as a grub screw if the entire screw fits inside a hole. Arguably, it depends on how the screw is used instead of the shape of the screw.
It might also depend on what kind of hex drive the screw has. If the screw has a hex drive (requires a hexagon-shaped screwdriver or allen key) then it is a set screw and not a grub screw.
Key Takeaways to Set Screws
Set screws are for attaching gears or pulleys to shafts. They are also used in ironmongery, joinery, doorknobs, and more.
Set screws do not have a protruding screw head. In some applications, this is necessary, as a protruding head would interfere with other parts.
Since a headless screw is not usually necessary, set screws are much less common than regular screws.
There are several types of set screws, and each type has advantages and disadvantages and is for different situations.