On 2011-08-20 13:46:19 -0400, "Paul" said:

a rectulanglar block, 6" long ,less 1/4" on each end for a border and I
want to evenly space 6- 3/4" holes

Here's a way to do it by only actually measuring two points. The rest
is mechaincal division.

SInce you're spacing 3/4' holes within 5 1/2 inches, you've already
defined a 1/4" border on each end. The radius of your hole is 3/8".
Thus, the centerpoint of each outer hole is 5/8" from the edge. Mark
those points.

Now, draw a line though each point, parallel to the ends of the board.
Since you're marking the center points of 4 holes and using the center
point of the other outer hole as your terminus, choose a number easily
divisible by five (like, oh, 7.5 or 10). Lay the zero point of your
ruler on one line. Swing the ruler until your chosen number lies on the
other line you've already drawn.

Then, just mark the correct divisions (1 1/2, 3... or 2,4, 6...) and
you've marked the center points for the other four holes. Draw lines
through those points and parallel to the ends crossing your center
line, and you're done.

You can, of course, tell people how brutal the math was in calculating
those points... but if you wanted to add the same dimension (x2)
outside your row of holes as between each hole, the math is more than I
want to deal with.