A grub screw (or set screw) is a small (often M3) screw that is used to secure components together where space is tight. Grub screws do not have a 'head' as such, just a hex key socket or screwdriver slot in one end.
Grub screws are often used to secure gears or pinions to shafts. It is a good idea to grind a small flat on the shaft in order to give the grub screw a better grip and reduce the chance of slippage.
Share your opinion