How to Build a Heavy Workbench

Position two planks of 50-inch 1-by-4 lumber on your work surface 23 inches apart and on their 1-inch edges. Insert two planks of 23-inch 1-by-4 lumber in between each end of the 50-inch planks, which will make a rectangular shape. Insert a third piece of 23-inch lumber between the middle of the two 50-inch planks.

Drill three pilot holes for 2-inch screws through the 50-inch plank sides into the 23-inch plank ends, then secure the planks together by driving 2-inch wood screws through the pre-drilled holes. Repeat with another two 50-inch and three 23-inch 1-by-4 planks so you have two rectangular frames. One frame will support the top of the bench; the other will serve both as a shelf and as braces for the bench legs.

Lay the shelf frame flat on your work surface and place a piece of 25-by-50 inch, 1/2-inch-thick plywood over it. The plywood will be flush on all sides with the edges of the shelf frame. Drive 2-inch wood screws through the plywood into the frame planks every 5 to 6 inches to secure the two together.

Turn both frames so they are resting on a 50-inch side. Position the shelf frame underneath the top frame, around 20 inches lower, with the plywood side facing toward the underneath of the top frame.

Place two planks of 35-inch 2-by-6 lumber, the bench legs, over both the frames. Position the top ends of the legs flush with the top of the top frame. The outer sides of the legs need to be flush with the ends of both the top and shelf frames.

Drill four pilot holes for 2 3/4-inch lag bolts through the legs into each of the frames -- so, eight pilot holes per leg. Fasten the legs to the frames by driving 2 3/4-inch lag bolts through the pre-drilled holes.

Flip the frames and two legs over so that the other 50-inch side of the frames is exposed. Place another two legs over this side of the frames and attach them to the frames like you did the first two.

Stand the bench upright and place a 29-by-50-inch piece of 3/4-inch-thick plywood over the top of the top frame. Secure the plywood to the top frame with 2-inch screws through the plywood into the frame underneath -- one screw every 5 to 6 inches or so.