Set screws appear with a variety of tip (point) types. The different shaped tips have different properties that engineers can utilize. If an engineer were to use a detent to ensure proper nesting of the screw, they might choose to use a cone point type of screw. One might often need to use a flat point when the screw must press perfectly flat against a surface. The most common type is the cup point. This type works well because the surface is rounded so that a small surface area is in contact, but it does not have extremely high stress at one point like that of a cone point. Durability studies show that the cup point offers superior resistance to wear while maintaining a strong grip. Knurled cup points offer the added advantage of a locking action (similar to that of a serrated lock washer) that prevents the screws from working loose in high-vibration applications.

Common points include the following:

• Flat point

• Domed point

• Cone point

• Cup point

• Extended point (pilot point, dog point)

• Knurled cup point

Knurled cup point

Knurl point screws are generally used to secure one object within another. The serrated ridge on the knurl cup set screw helps reduce loosening due to vibration. The knurled point combines digging action of the cup point with counter-clockwise locking knurls that have a ratchet-locking action which helps resist loosening, even under the most severe vibrations.

Knurl point set screws should not be reused because the cutting edges of the knurls are deflected when tightened. During removal, the cutting edges are torn and no longer have full strength to resist unscrewing. ISO standard for Knurled cup point set screw is ISO 4029.

Set screws are made with a variety of drive styles, including the following:

• Straight slot

• Hex socket

• Square socket

• External hex

• External square

• Bristol spline

Set screws common points

Machine Screws