John Quinn asks why are some straight edges beveled.

The beveled ones are for layout ie. drawing straight lines or
applications where you don't need it to stand on edge.  The nonbeveled 
ones are for inspection type work where it is helpful to have it stand
on edge for candleing or using feeler gages.  And I will gladly pay you
$12 each for those babies. I'v got to get out more ( h@l... any ) to the
flea markets.
Ken
in Ypsilanti