Quote Originally Posted by reefy86 View Post
noob question here with it being the first time tapping a hole my self if the linear rails holes are 4.5mm what would the tap size be to the aluminium plate its attaching to?
I didn't think they would be that small, an M4 screw is pretty weedy, there must be lots of them. As a good rule of thumb tap drill size is screw diameter - thread pitch, so for M4 normally 0.5mm pitch would mean a 3.5 mm drill.