Intro: The Very Rigid $45 Eight Foot Workbench
Your shop needs a good workbench. It needs to be rigid so you can trust it to hold any project you are doing. It needs to be big so you have room to work. It needs to be inexpensive so you have more money for tools.
I built this bench for under $45 using all new materials in the spring of 2011. The top is eight feet long and two and a half feet deep. The shelf is full length and one and a half feet deep. The tool ledge is three and a half inches deep.
Note, this Instructable will use the US standards: inches are marked as ", feet are marked as '.
2"x4"x8' (nominal size) 7
4'x8'x3/4" particle board 1
Box 2" exterior wood screws 1
Bottle of wood glue. 1
Saw (hand or power)
Good to have
Countersinking drill bit
Workmate style clamping table
Larger pieces of cardboard
Step 1: Step 1 at the Lumber Yard
The 4'x8' panel can be particle board, MDF, or chip board. I chose particle board as a good compromise of cost and durability. Buy from a lumberyard or big box store that will do free cuts with a panel saw. Have the store cut the panel lengthwise at 30". Panel saws do nice straight cuts if the operator is even minimally competent. Not only will this result in a better cut than you can make with a portable saw, but it will also make the parts lighter to cary and easier to maneuver.
Step 2: Step 2 Cut Legs and Braces
Cut the legs and the cross braces. You need to cut four legs. I like the height of my table at four feet. This is the first place where there is a "gotch'a" if you are not use to working with wood. Eight foot 2'by lumber is not eight foot long. It is considered framing lumber and so is cut shorter so that it can be used to frame an eight foot ceiling height with a sill and double top plate. The result is that they are actually 94 5/8" long. Because of this, you can not simply cut the board in half.
Fortunately, you also need to cut four horizontal braces. These braces need to be 22" so you can cut two braces each from two of the scraps left from cutting the legs.
Step 3: Step 3 the Tool Ledge
Next, build the front tool ledge. This ledge serves two purposes. First, it provides a place to put the hand tools you are using where they won't get burried under the pieces of your project. More importantly, the ledge makes the front of the table very stiff.
Start by cutting the 1"x6" to the same length as an 8' 2"x4". Since a 1"x6" is not a framing size, it is really 8' long. By cutting it to the same length as a 2"x4", we can use corner clamps at the ends to make the ledge completely square. This is important to keep your tools from falling off it (and on to your foot).
Brace a full length 2"x4" vertically either in a bench clamp or by clamping it to the legs of another table. If you have corner clamps, position them at the right heights on the ends by using the scrap piece you cut off the 1"x6" as a guide. Remove the scrap by turning the screw on the part of the clamp which was holding it several turns.
Put a wide bead of wood glue on the top edge. Glue is cheap. Glue is strong. Glue can be cleaned up. Don't skimp on the wood glue. Slide the 1"x6" in. Start it at an angle so it doesn't push the glue off. Tighten the corner clamps. Using the measuring tape or the square, mark five locations for screws along the length of the board. The screws should be about 3/4" from the edge (2 by lumber is actually 1 1/2" thick). The screws provide clamping force to allow the glue to spread evenly and provide a good bond.
While the glue is still wet, use a wet towel to remove the excess from both sides. Wood glue is water based, using a wet towel will allow you to clean all of it if you get it before the glue gets too hard.
Step 4: Step 4 the Table Top
Now it is time to frame the table top. Along the back side we are going to place a full 2"x4" board vertically under the table top. The easiest way to do this is to place the 2"x4" on the floor, on top of some large pieces of cardboard (to protect the floor from wood glue), take two of the legs you cut and place them at 45 degree angles to this board, and set the table top on top of them. Move the back 2"x4" so that the edge of the table top is resting on the first quarter of an inch of the board and the board is centered along the length of the table top. You are going to add wood glue to the top of the board and then carefully lift the edge of the table top and slide the board in until it is flush with the edge. Try this BEFORE adding the glue. Watch your fingers and toes since the table top can shift unexpectedly.
While the weight of the table top provides a lot of clamping force, I chose to still run a wood screw in approximately every two feet like we did with the ledge. Wipe off the glue you can reach with a wet towel.
Next we need to put two of the short braces we cut under the sides of the table top. We want the outer edges of the braces to be flush with the outer edges of the back 2"x4" (the last picture is a view from the side of the bench). Use the measuring tape or square to make sure the brace is an even distance from the table edge. Glue and screw it to secure it into place.
Step 5: Step 5 Legs and Braces
Turn the table top over. Now we are going to install the tool ledge, the legs, and the remaining side supports. We'll start with the back legs. Place a level on the table top to make sure that it is sitting level on the cardboard you are using to protect your floor. Place cardboard shims as necessary to make it lay solid and level. The rear legs are attached with glue and screws to the 2x4's that stiffen the table. It is more important to have the legs perfectly vertical than it is to have the top of the leg in contact with the table top over it's entire area. Temporarily place the leg in the corner. On my table, I ran the 4" (3 1/2" actually) dimension fore and aft. This will give more contact area for the brace we will be adding later. Mark where the leg edges are on the other 2x4's. Remove the leg and coat the ares you marked as having been covered by the leg with glue. Use two 6" clamps to clamp the leg to the two 2x4's. Think some about where you place the clamps because you are going to be running screws in right next to them. Place a level along the leg, a post level is handy for this. Adjust how the leg is clamped until the level snows the post being completely vertical in both directions. Once it is vertical, drill holes and drive in screws through each of the 2"x4" braces into the leg. Think about where the screws are going inside the leg so the don't hit each other. I run three in a triangle pattern from one side, with the base of the triangle being furthest away from where the other screws enter the leg. I then run four screws in a square pattern in from the other direction. Repeat this on both rear legs.
For the front legs,you only have one 2"x4" to connect the legs to at this time. You want the leg flush with the front of the other brace because you will be attaching the tool ledge to both of them. Glue, level and clamp the leg similar to what you did on the back legs. Use a triangle pattern again for the screws.
Next, attach the remaining side supports between the front and rear legs. These supports will determine where your shelf will be located. I placed them about a foot from the bottom (top, at the moment) of the legs. Mark the distance on both legs, clamp the support to one leg, and use a level to move the other end as necessary to make the support level. I used only screws to secure these braces and not glue. It is better to do both, but it is difficult to do the leveling by yourself quickly so I skipped the glue.
Finally, attach the tool ledge. I put glue on the part of the legs and end of the side supports that will touch the tool ledge, clamped it into place and added screws to finish. Adding glue to the edge that makes contact with the table top is optional. The otherwise unsupported mass of the table will cause it to push down onto the ledge anyway.
You can now turn the table upright. Be careful, it is heavy.
Step 6: Step 6 the Shelf
Finally, we build and install the shelf. Like the table top, the shelf will have a 2"x4" running along it's back edge. However, we will run this one on the top instead of the bottom so that it will also act as a back stop. Install it the same way you did the one on the back of the table top. When. You slide the shelf in, you will find that it doesn't fit if you oriented the legs like I described. That's OK. Slide the shelf in until it is flush with the table top on both sides. Mark the shelf just to each side of each of the front legs. Measure the inside distance between the front and the rear leg. Measure the side of the shelf. The difference between those two measuremets is how deep of a notch you need to make in the shelf to fit around the front legs. If you make the notches tight around the legs, it will help stiffen the table. Cut the notches, put glue on the top of the side supports and push the shelf into place, you might need to use a small mallet if it is a tight fit. Add some wood screws to finish clamping the shelf in place.
That's it. You now have a very solid workbench. If you want, you can add some 1"x4" planks vertically on the back side to hold peg board. Most big box stores carry peg board in 2'x4' cuts so three 1x4's each about 28" long would support two of these panels.