4x8 Work Table

Screw a 3-1/2" 2x4 block to the bottom of each leg with two 2-1/2" screws — these are the caster mounting pads.

Option from the source: skip the blocks entirely and put the bottom shelf at the very bottom of the legs, which buys more clearance under the shelf.

Join the legs in pairs with the 42" cross supports, two screws per joint, making three identical H-shaped leg sets — two ends and a center.

Attach the 96" rails to the leg sets, centering the middle leg set. Check the legs are square to the long rails as you go — the 8-foot span amplifies every degree of error into visible lean.

Cut the corner and center notches out of the plywood shelf with a jigsaw so it drops around the six legs — about 3-5/8" x 3-1/2", cut 1/8" oversize so it slides in without a fight.

Then screw it down with 1-1/2" screws, USING THE PLYWOOD TO SQUARE THE FRAME: the sheet's factory corners are the truest right angles in your shop, so pull the framing to the plywood, not the other way around.

Screw the upper 2x4 cross pieces to the tops of the leg sets — the beginnings of the top frame.

Clamp the upper 96" rails in place before screwing. The source build hit the classic snag here: one leg out of square made the 8-footer 'come up short' — the fix is loosening the leg's screws, pulling it true, and re-driving.

Do not shrug this fit off. The melamine top is a rigid factory rectangle; if the frame under it isn't the same rectangle, the top rocks or overhangs unevenly and there's no trimming it back.

Cut the six filler pieces to fit your actual openings (the listed 14-1/2" is nominal) and screw them in from the inside so the fasteners don't show on the finished table.

With help, tip the table and mount the six casters to the leg blocks with their screws and washers. Lock all six before the next part.

Set the melamine sheet on top — at 97" x 49" it overhangs the frame about 1/2" all around. Fasten with a few 1-1/2" screws down through the top; countersink them slightly so nothing stands proud of the work surface. (The source builders left theirs loose, planning to bed it in silicone like a vanity top so it can be replaced when it wears — a reasonable long game for a surface that will take abuse.)