Hardware, Oils and consumables

Grub screws are used where the end of the screw, not the head, provides the tightening force and where the depth to where the screw engages is variable. Their use may also be for decorative purposed where a visible head would be unsightly or where such a head would interfere with a smooth surface such as attachment of a handle to a shaft. 

As can be seen in the diagram, the operating end of the grub screw can be many shapes depending on the purpose of the point of engagement, for instance when the piece being attached needs to be in one position only a dog engagement would be used, and where the engaging part is intended to clamp, such as a die in a die stock, a pointed end is usual. Where the part being secured may be in multiple positions on a shaft, an oval for flat end would be desirable.

Historically drive would be provided by a screwdriver slot, but more commonly these days a hexagon (Alan) key slot is provided.