Drilling holes in steel tubing

Hello everyone,

I'm back in the shop again with a new problem. That is, how to drill
accurate holes on-center through steel tubing.

I need to attach 2 short lengths of 1/2" EMT tubing parallel to the top
tube of a bicycle frame, one on each side. The EMT tubes will extend
about 20" forward of the bike frame. The frame tube is about 1" dia. I
want to drill horizontally through all 3 tubes and attach everything
with a pair of #10 machine screws.

Prob. is how to drill the holes on center so everything lines up. I
have both a drill press and cordless drills at my disposal.

Suggestions? Methods? Tools?

Thanx,
Harry
Wright Brothers Bike Guru
Wright 1902 glider
Wright 1899 kite