Kilibru,
Put your calculator away...look around and remember that some of our very best buildings were crafted by men with little of no education...
I have a homemade allignment jig that's not handy to show a photo of...but it's simple enough to describe and easy make or redesign...
I have 4 inch brass carraige bolt that's sharpened to a point, with a nut and two fender washers...you simply screw it together through the centerhole of your drill press table, with the point up...then you carefully allign your drill bit, so that it lines up with the brass point. Using a small centerdrill, carefully start the whole at both ends with an egg beater (be careful if you use a cordless drill)...
then using you drill press, set one started hole on the brass center and drill the other hole, while being carefull to hold the stock steady.
I drill it undersize then ream it out with the correct drill bit in a cordless when I'm actually fitting the screw.
Fast, accurate, and inexpensive.
