I just moved to Chicago, and, while I look for full time work, I have started volunteering at the ReBuilding Exchange ( http://www.rebuildingexchange.org.) They are an salvage warehouse, selling architectural elements from demolished houses, furniture made from reclaimed lumber, and old, but still useable appliances. RX also trains ex-offenders in job skills, including woodworking. I've written some more about their work and my participation in it on my new blog, found here: http://www.objectguerilla.blogspot.com.
Their furniture line, RX Made, concentrates on fairly simple furniture pieces that can be built from what they have available in the warehouse. Complicated cuts, fancy joinery, and fine finishing are outside the skill level of the job trainees and the tools available in their still-new workshop.
Their current bench design is simple and straightforward, but relies on end-grain joints of questionable strength. I prototyped some new benches for them, three in all, in an attempt to reduce the amount of materials, store-bought fasteners, and time needed to make each one. You can knock these out in an afternoon, providing some solid seating for your mudroom or deck. They are a great beginner's project that will acquaint you with a few common power tools and give you a dose of confidence so you can move on to something more complex. Even if you buy the materials off-the-shelf, each one of these benches is super-cheap so you don't have to worry about messing up. Lastly, don't be intimidated by the tools list: you can build all three of these with nothing more than a drill and a circular saw if that's all you have available.
These directions concentrate on the two benches that utilize grooves to hold the legs in place; the lag-bolted version is fairly self-explanatory from the pictures. Just cut some slanted legs and shoot it through with big fasteners.
You will need these materials:
1 2" x 10" x 8' board per bench
1 2" x 4" x 4' board per bench
A handful of 2-1/2" drywall or deck screws
A handful of 3/8" x 5" lag bolts and washers
Some thin scrap wood
You will need these tools:
Chop saw or circular saw
Router with flush trim bit
Assorted bits appropriate to your fasteners
Step 1: Cutting and Sanding
First, cut the tops for your benches. These are 48" long. That length makes space for a few people to sit on them, and also allows you to get both the top and two legs out of one eight-foot board.
Use a chop saw, if you have one, for a nice square cut. I take an inch or two off the factory ends to re-square and clean up the board, as those ends can often be rather rough.
Take a sander to the tops with 60, 80, or 100 grit paper, depending on the condition of the lumber. If you are planning to finish the wood
-- if the benches are for outdoor use, for instance -- work your way up to a 120 grit for a super-smooth surface. The screwdriver in the second picture was used to lever out old staples, a hazard of using reclaimed wood.
Step 2: Groovin'
For maximum strength, I routed some grooves that allowed the legs to notch into the top and vice versa. This eliminates some of the weaker end-grain mechanical connections in the previous design, provides a cleaner finished appearance, and minimizes the number of store-bought fasteners needed. These joints are very simple, and, if built tightly, extremely strong.
I used a plunge router with flush-trim bit. This type of bit has a smooth piece at the top of it, the same diameter as the cutting part of the bit, that acts as a guide. By clamping some scrap lumber to your workpiece, you can create an extremely precise template.
Find the center of your top, then measure 18" off of the centerline to either side. Now measure a further 1-1/2" to each side. This will be the width of the notch that accepts the legs. Line up a piece of 1/2"-thick scrap on either side of your future groove. Screw or clamp down to the workpiece. Set the depth of the router to cut roughly halfway through the depth of the workpiece. Turn it on and draw it toward you in slow, even strokes, making sure the smooth part of the bit is riding tight to your guide board. Once done, sand out any router marks in the groove to even it up.
If you don't have a router, you can use a circular saw to do the same thing, albeit a little less cleanly. Set the depth of the blade down to 3/4" and make a series of passes with the saw right next to one another between your marks. Break out the chips and clean up with a chisel and sandpaper.
Step 3: Legs!
Cut your legs on the chop saw to 17-1/4", which will give you a finished bench height of 18". It can be a little shorter and be comfortable, but don't go any higher. If you're making the version where the top notches into the legs, cut them at about 21" or so, then follow the same routing directions discussed in the previous step to make grooves 18" from the bottom of the legs.
Set up a stop so the legs are the exact same height; measuring off of the blade of the saw, clamp down a scrap of board 18" away. Now, you can just slide your workpiece against the stop, chop, and voila, one piece after another that is perfectly congruent. Keeping the legs the same length is crucial to keeping the bench from rocking once assembled.
Strike a centerline that splits each leg vertically. Measure 2-3/4" down from the top and mark, then drill and counterbore for your eventual lag bolt to the crossbar. The diameter of the lag is less important than its length, with about 5"-6" being ideal.
Once your legs are cut, slap some glue in the grooves and pound them into place with a mallet, protecting the leg from denting with a piece of scrap.
Step 4: Crossbarrin'
The last step is to put the crossbar in. This piece, made from a 2" x 4", keeps the bench from rocking side to side. The basic shape is a rectangle, where the bench surface and the ground describe two sides and the legs describe two sides. WIthout the crossbar, the grooved joints would loosen up over time, and the bench would deform into a parallelogram, with the legs slanting over and the whole thing collapsing.
You've already space your legs so a 3' crossbar should just drop in. Run a centerline up the inside of each leg with your square. Mark center on each end of the 2" x 4". Evenly space out 3-5 holes on one narrow side of the 2" x 4". Counterbore holes about halfway through the depth of the wood. Run some glue down the top edge of the crossbar, then position it so the centerlines match the centerlines on the legs. Pop screws in each hole, which will hold the crossbar to the top without showing the fasteners from above.
Now, push a pilot hole through the holes you already drilled in your legs, and lag the legs to the crossbar. It is crucial to attach the legs to the crossbar or else the crossbar won't serve its fullest purpose.
Now you can sit down and try it out!