Say you want to drill access holes perpendicular to the axis of a standard T-Slotted extrusion for the purpose of screwing it to the end of another extrusion of the same type. The 2nd extrusion is tapped at the end for say an M5 screw and the access holes are for Allen Key access. What kind of screws are used to tie the two together and is a T-Slot nut involved or not? I would think that it might just be a pan or button-head screw that straddles the far T-Slot edges with the rims of the screw's head to tie the two together. Just trying to understand how this connection method works. I grabbed the image below off Phiget's T-Slot Primer. The primer says that the holes are only for the Allen Key to get to whatever it is tightening. It doesn't explain what other hardware is involved. Is this what a "Socket Head Cap Screw" is for?