Re: [CAD_CAM_EDM_DRO] Re: Flat surface creation revisted

I had considered a concrete base for my router table. As the design grew to
ten feet long I decided this was going to be too heavy. A concrete slab
will work but you will still have to create your way surfaces after it
cures.

Concrete shrinks quite a bit as it cures and thus will not be flat no matter
how thin you pour it. Also, you want the mix rather dry, as wet mixes
shrink more and are not as strong when cured.

Don't forget to use methyl methacrylate in your concrete. This
substantially improves its properties. MMA is also available from that art
supply under the name of "Art Medium Type A".

You can obtain a good, flat surface by starting with concrete and then
pouring epoxy over it after it fully cures. The epoxy will self level and
doubles as a swarf board. When it gets chewed up just clean and pour more
epoxy on it.

My router table (which is still in a bazillion pieces) has a 3/4" steel
plate for the top. The frame is 48" wide and the top is 56" wide. The
linear rails mount upsidedown under the 4" overhang, bolting right to the
plate in grout bedding. The plate will be bedded in epoxy grout on the
frame. I'm estimating about 4000 pounds total machine weight.

The inverted rails are easily shielded from dust and swarf. Hiwin rates
their rails the same for all positions.

Doug