Ever since I bought my CNC last winter, I wanted to upgrade the bed. I've been using 2 layers of 3/4 MDF. Had to route channels to put in T track so I could use hold downs on the work.
Bought some 3/4 X 3 80/20 aluminum extrusions. Took off the old bed, cut the new pieces to length. Then wanted to get everything as level as possible.
My father was a machinist, tool and die maker and then a CNC programmer. I have some of the tools he bought when he first started as an apprentice. Got to use them today. Found out that there is .004 difference between the high and low pieces so I need to get some shim stock tomorrow, .001, .002, .003 and .005 to get everything on the same plane.
Here is a pic.