Purchase one of these to mark your holes: Center Punch - Automatic Center Punch with Brass Handle

Then drill a small pilot hole (3/32" or so), then 11/64" for the M5x0.8 tap. Harbor Freight taps are fine. Their drills leave a lot to be desired. Get your drills from McMaster or Fastenal or MSC or Grainger or similar Industrial Supply company.

After drilling, counter sink the holes slightly on both sides before tapping with a 1/4" drill bit by hand, not in a power tool. I have one of these: http://uytit.files.wordpress.com/201...rill-chuck.jpg that I use for holding drill bits for manual operations. Less than $10-

Use lots of oil both when you drill and when you tap. Any light oil is fine - I usually use TriFlow liquid - not spray.

Flush the oil out with Isopropyl Alcohol (from any pharmacy) just before you install the rack, and use blue or purple thread locker. That will protect the cro-mo and retain the screw, while still being removeable. DO NOT use red threadlocker - you will not be able to remove the screw.