What size radius should I make for the slot for an aluminum block

DIN923 Slot Cylinder Shoulder Bolt Step Screw M3 M4 M5 M6 M8 M10, Find Details about Bolts, Shoulder Bolt from DIN923 Slot Cylinder Shoulder Bolt Step Screw

M3 , the driving

m3 slot EXPANSION SLOT 1 X PCI Express X16 Gen slot 1 X PCI Express X1 Gen slot 1 X PCI slot Storage Support by AMD® A55 Express Chipset RAID0

m303 slot The mounting is suitable for direct mounting on the mounting profile The screw heads of the slot nut screws are inserted into the T-slot, and th