these images show a steel table that I fabricated. It is built EXTREMELY STRAIGHT and will have a life span much greater than myself. The last picture shows a little tab sticking out under the top plate. This is just one of MANY shims to get the table perfectly straight. The table is 2 ft x 8 ft long...over the span of 8 ft, it is within 10 thousandths of an inch....

a table like this is expensive to build, but if you do a lot of building, you shouldn't do without.