Lawrence M's Table Bed Support

The scratch build CNC Machine calls for two sheets of MDF that is sandwiched together to strengthen the table. The way the book CNC Machine is designed, there cannot be much structure underside the bed of the machine because the gantry spans underneath the bed and is where the gantry connects to the x-axis lead screw. This only allows for the front and back of the table to have support. Lawrence fixes this with a metal structure that is ribbed and runs along the length of the table. Here is Lawrence's information on this fix: I had mentioned to you that I had removed the sag in the 48" suspended bed by inserting an iron grate under the bed and pressing it up underneath with supports that were about 1/4" higher than the end pieces from the original design. This made the entire machine weight bear down on the grate as it was lifted off the table by 1/4". I also added 8 bolts/nuts to ensure the new supports didn't collapse with vibrations. You can see the end of the grate supported by the piece of phenolic plywood behind the original end supports. It lifts these old ends up 1/4" off the table and brings the weight of the machine down onto the new plywood and grate (1 inch thick.) There is about 1/8" space between the grate and bottom of the gantry. I thank you for your planning for my addition in your original drawings! The pattern of 8 screws is the bolts that keep the plywood from twisting or falling out. The grate is pressed in and not fastened. I mentioned to Lawrence that the iron grate would also be a great addition if only one layer of mdf (or plywood) were used for the table. That configuration would recoup 3/4" of space for better gantry structure and reduce the weight of the table. It would also make the table stronger by reducing the dead load above the iron grate.