The first step in building the open-grid platform is the outer frame. You can build this project out of dimensional lumber, or use plywood as seen here. All of the wood for this project came from two sheets of 3/4 inch AC grade plywood. Ripped into 2 1/2 inch wide strips, one sheet will provide enough material for this platform and the legs. I ended up needing just a few more strips to complete the box supports as needed for this platform. The rest of that sheet can be used for risers and subroadbed to support the track itself.
You can make the plywood strips on a table saw or with a circular saw and guide. One advantage of working with plywood is consistency of quality. If you are careful in ripping your boards, you will have a very strong and stable benchwork building block.
Building the Frame
Start by cutting the four outer pieces to length. Use a miter saw to put a 45 degree angle on each corner. The outer length should be 94 inches and width 46 inches. You can shave a little off of these dimensions for a more loose fit in the support frame if desired (1/8 to 1/4 inch would be plenty.)
Next attach the four corners.
- Align the two pieces carefully and check with a square.
- Apply wood glue to the joint.
- Having a pneumatic brad nailer available, I put two 1 1/4 brads into the joint (one each direction) to help hold the alignment during the subsequent steps. Having a second person help hold the corner square will work just as well.
- Drill pilot holes for three screws. Use a 3/32 drill bit. Alternate the screws front / side / front.
- Use a countersink bit to clear a beveled hole for the screw head.
- While holding the joint square, install three 1 5/8 inch drywall screws. Insert each to within about 1/4 inch before tightening them all. It will be easier to maintain a square corner.
