[Kevin Sevcik]

Originally Posted by teachsail

Like most hand produced but repetitive tasks this job can be improved with a jig for quick alignment of the holes. Here is one example of how it could be done, no markings necessary.

http://www.diynetwork.com/how-to/uni...ess/index.html

The problem with a jig for this is tolerance stackup. If you're drilling 50 holes 0.5" apart you'll be an entire hole off by the end if your jig if consistently 0.010" off. If you're marking every hole by hand, you can be off by 0.010" on each hole and it won't matter much because that's 0.010" off the true dimension, not the distance to the last hole.

If you want a really long setup, you could make a similar jig and use a previously drilled bar as an indexing plate. As long as you use the same bar as your indexing plate, all the copies of it would be pretty similar.