Surfacing the table

[gixi]

Copied from elsewhere:

Well in order to be correct to all members I should wait a few days to make some SMALL adjustments to the X rails.
What happened ? After finishing the small cuts I put the bit on zero. Then using the jog I start to move the spindle along X and Y axis. Surprise :eek: ! In some area is not touching the table and in other to much. When I remeasured the X rails I found small differences in the height of the rails (27.5mm, 27,8mm, 27mm, etc.). So for the moment I send the rails to a metalworking shop to fix that.
But this is a small issue compared to the beautiful moment when something appears on the wood :D!
At the end of the week everything should be set properly.

[Gerald D]

Marius, we do not worry about small differences in rail height . . . .

First we screw the rails down as straight as what we can. Normally we have to add thin plates (shims) where the rails are too low, or where the big channel irons have problems. With the shims we can get a very straight rail. A popular shim is cut from a beer tin/can.

Then we take a 25mm cutter and cut the whole table surface to be parallel to the rails. We call this "surfacing" or to "surface" the table.

So, with a combination of shims and surfacing, the cutter runs exactly parallel to the table.