I figured half a page of map printout is 5 1/2 x 4 1/4 inches, so I added
3/8
inch on all four sides and came up with 6 1/4 x 5 for the Lexan blank.

I had about a 16 x 20 sheet so I clamped a bar across the stock at the
four
inch mark and set to the usual v grooving with the back point of a sharp
craft
knife. No joy. So I deepened the score with three passes with the point of
the
knife. The bar was right at the edge of my 1/2 inch thick overhanging
bench, so
I leaned on it an it snapped cleanly. Then I did the same for two six inch
piece from the four inch width.

I actually very surprised that it broke at all by scoring it...it usually
will just bend.

Unless you actually had a piece of plexiglass.

Mike