Faced with the problem of drilling two rows of holes that were 1.125" apart and  a hole every 6.0 in. 
in a 1"x6"x12' piece of cold rolled steel this is what I came up with.  

Hole drilling shows the overall setup with the work in process.  
The engine hoist was necessary to keep the bar from sagging.  The other end had a roller stand to support it.

Hole drilling 1 shows the setup on the table.  To start the process the first hole was laid out on the bar 
and located above the L bracket to the left of the vise. The vise was tightened at this point.  This hole 
was drilled through the bar and into the L bracket.  The table was moved 6.00", all axis were locked and 
the next hole was drilled.  Now the vise was loosened and the bar moved until a shoulder bolt through the drilled
 hole and into the L bracket located it. Tighten the vise and drill.  Repeat for all holes along the length of the bar.
When the holes were done along the length of one side the table was moved the 1.125" in Y and the process repeated up 
the other side.

Hole drilling 2 is a view from the other side.  In making the L bracket the height was milled to the same 
height as the vise.  A level was used often during the process so that the holes were as near perpendicular 
as we could get.