How to Build a Big Bench

Measure the area into which the big bench is to be installed and then transfer the measurements to graph paper and draw a plan of your project. You will need four heavy stretchers -- such as 8-inch by 2-inch lumber -- to frame both the long sides of the bench top and the long sides of the leg brace frame. You will need four heavy runners of the same size to frame the short sides of the top and brace frames. You will need at least four legs approximately 36 to 40 inches long; 36 inches is the height of a standard household worktop. If the bench is to be very long, you may need additional pairs of legs to build a central support.

Calculate the amount of lumber required to build the bench top. You will need lengths adequate to reach from one runner to the other. You will need sufficient width to cover the distance from stretcher to stretcher; if the stretchers are 24 inches apart and you are using six-inch wide lumber, you will need four pieces as long as the bench.

Purchase the lumber and sufficient hardware to complete the project. Buy “finished” lumber so there will be no need to plane or sand the wood. Staff at home improvement warehouse stores and lumber yards should be able to advise you as to whether a central support would be advisable for your specific project.

Home improvement warehouses sell galvanized hardware for constructing exterior decks, which doubles well for workshop projects. You will need four 45-degree angles to assemble the bench top frame, four to assemble the leg brace frame, 16 more to fix the legs in place without central support, and 24 more for a bench with a central support. This equals either 32 or 40 angles in total. You will need size 8 countersunk screws twice as long as the bench top boards are thick; if you are screwing two-inch timbers down, use four-inch screws. You will need one-inch size 8 screws equal to the number of holes in all your 45-degree angles added together. All the screws should be galvanized deck screws.

Use a circular saw to cut all the lumber to size. Sand each cut to minimize the risk of injury from splinters. Lay out the components -- the stretchers, the runners, the legs and the bench top boards -- in separate piles.

Dry assemble the bench top frame on a flat, level floor, positioning the runners inside the ends of the stretchers for strength. Use a power screwdriver to screw a 45-degree angle into every inside corner -- deck screws are typically sold in packs that also contain the correct bit for driving. Repeat the process to create the leg brace frame; you should then have two frames of exactly the same dimensions.

With the bench top frame flat on the floor, position a leg in one corner and fix it in place using two 45-degree angles, one to each inside corner. Repeat the process with each of the four legs.

Lift the leg brace frame over the bottoms of the legs -- which are uppermost at this juncture -- and slip it half way down the legs. It is usually convenient to have another person help with this part of the process. Fix the leg brace frame in place using two 45-degree angles on each leg, just as you fixed the tops of the legs into the bench top frame.

Fit the central support legs at this point, if they are part of the plan. Measure and mark the middle of the stretchers, hold the legs in place one at a time, and use two 45-degree angles at each joint: two at the bench top frame and two at the leg brace frame for each leg.

Turn the assembled frame right-side up. Working one piece at a time, position the bench top boards on the bench top frame. Use an electric drill and pilot drill bit to make holes for the screws through the boards. Use a power screwdriver to screw them into place.