Many of our T-slot Aluminum Extrusions, such as # 10-4545-0, come with centerline tap guides, self tapping ends and standard T-slot size. Although when used with one of our Speedlock hidden profile fasteners such as # 41-002-0, milling, dripping and tapping are not required. However, when it is preferred the centerline tap guide keeps holes centered & straight which means a better stronger frame in the end. Many of our aluminum profiles also feature self tapping ends.  When using fasteners with M8 thread, tapping is not necessary.  Simply screw the fastener in to secure the connection. All our profiles also feature a common t-slot size which saves you time by not having to have multiple size connectors and fasteners. Check out our online catalog for more information on our innovative aluminum profile system.