Common types of set screws you might encounter include all the varieties listed below. Their respective uses are also noted in each case:
Plain Cup Screws
Cupped set screws have a slightly concave recess in the flat end of their tips
The thinner circumference of the cup is where all the pressure is exerted against the rear component, as opposed to the entire flat tip making even contact
This design helps to provide good torque and locking force against the object being pinned while minimising the risk of damage to the screw shaft end through over-tightening
As force is exerted over a smaller, sharper area with a cup set screw than a flat end screw, there is a higher chance of marking the component or surface which is being fastened
Plain cup screws are one of the most common types of set screw in widespread use
Knurled Cup Screws
Knurled cup set screws behave similarly to plain cup screws except that the outer edge of the cup also features jagged teeth (knurling)
The knurling is designed to bite in the surface that the screw is butting up with, providing even stronger grip through a ratcheting action
They are particularly useful when there is a risk of a standard set screw working loose over time, for example, in applications exposed to high vibration
As the biting action of knurled cup set screws will cause significant surface markings on fastened parts, they are usually chosen for use in permanent or semi-permanent assemblies
Knurled cup screws should not be reused once removed as the serrated teeth of the knurled design will be damaged in the process of unfastening the screw
Flat Set Screws
Flat point set screws are made with a completely flattened end
The flattened end provides a more evenly distributed compression force where the tip makes contact with a base surface
Flat point set screws tend to cause relatively little damage to the parts or surfaces they are pinning since the tip does not penetrate the surface to any significant degree
Flat end screws are reusable since removing the screws does not damage them in any way
Oval Set Screws
Oval point socket set screws have a rounded, slightly convex tip. They are sometimes called domed point set screws
Their design is intended to minimise the risk of damage to surface and components being locked in place
Oval point screws can also allow for easier adjustment without having to completely remove or reset the screw. This is because the smaller, rounded point of contact makes movement against the fastened surface somewhat easier than with a flat end
Cone Set Screws
Cone point set screws are sharpened at the tip and designed to penetrate the underlying surface to a degree
This wedging in function means that they provide some of the strongest grip of any socket set screw design in terms of both axial and torsion forces
Since they are inherently damaging to sub-surfaces, cone point set screws are almost exclusively used in permanent fixtures, or sometimes as a hanger or pivot
Dog Point Set Screws and Half-Dog Point Set Screws
Dog point set screws and half-dog point set screws have a lengthened, protruding tip or nose that is flattened out at the end. They are sometimes called extended point set screws for this reason
The protrusion on a dog point set screw is longer than that of half-dog screws
These extended ends are intended to fit into an equivalent sized hole or recess in the underlying material surface, similar to a dowel
They are effectively a halfway house between a standard flat point set screw and a sharpened cone point set screw
They are intended for use in permanent or semi-permanent settings, although they can potentially be removed and reused in a suitable location
Soft-Tipped Set Screws
Soft-tipped set screws have a softer and more malleable end section than the main body of the screw
This design enables the soft tip to deform against the surface material as the screw is driven into place, enabling better locking grip on uneven or non-flat surfaces
The tip can either be made of softer metal such as brass, or of other materials altogether. For instance, nylon-tipped set screws are common
Ball-Point Set Screws
A full ball-point socket set screw features an actual ball tip embedded into the end of the screw
This type of set screw can be useful when two non-parallel surfaces or materials need to be clamped firmly together