Almost everyone knows what sawhorses are and what they're for. They raise your work off the ground to make it easier to work on and keep your expensive tools out of the dirt. They should be easily portable for on-site work. They're also handy for supporting sheet goods while you're cutting them. There are plenty of sawhorse brackets for sale, made of sheet metal or plastic and some of them are quite good. The complete sawhorses I have seen for sale are either very flimsy or solid but rather expensive. The complete ones are often made of steel which requires extra care in use or a lot of replacement saw blades when they hit the sawhorse. The ones I've seen do not have replacement parts. Once it's damaged, the manufacturer intends them to be thrown away and replaced.
I can't claim to have originated this design for sawhorses - I've seen similar ones in workshops and on construction sites for many years, but I believe I've made some improvements in their construction and an modification/addition that makes them more useful. These sawhorses are made of inexpensive 2x4 construction grade lumber except for some scrap plywood, and some screws. They set up and knock down quickly and easily to take up a minimum of space, and provide almost as much support for sheet goods as a large work table. The entire system can easily be built with a table saw in under an hour for about $30 once the cutting jig is made out of some scrap wood. I based all the dimensions here on sawhorses that are 30" tall and 48" wide, which are both taller and wider than most commercial sawhorses. Since the top edges of the cross pieces are often cut into during use, I've found that it's better to make them easily replaceable.With these, the top surfaces of both sawhorses can be replaced in minutes for generally about $5-6.
Step 1: Materials & Tools:
To make a pair of sawhorses with the additional cross pieces to support plywood, particle board, etc. you will need the following:
6 - 8' x 2" x 4" (if you want taller sawhorses, replace two of these with 10' lengths)
1 pc. 3/4" plywood 3-3/4" x 48"
40 - 2" flat head wood screws or drywall screws
4 - 1/4" x 4-1/2" Hex Head bolts with nuts and washers (optional)
If you don't know what these things look like, you shouldn't even be looking at this Instructable.
You will need a table saw capable of at least a 3-1/2" cut (most 10" saws will do this). You'll also need a measuring tape, electric drill and bits, various screwdrivers to fit the screws you'll be using, and a plane (or a belt or disc sander). As with many Instructables, there are other ways and tools that will accomplish the same things; this is just the way I did it.
Step 2: Making the Jig to Cut the Sawhorse Legs
Because the design calls for a 20° bevel on the top ends of the sawhorse legs, it is considerably beyond the normal adjustment for table saws (or even miter saws), which only cut to about 45° or 50°. By making a fairly simple jig, these cuts can be made easily and safely, working with the 2x4 standing on edge. The jig is pretty simple, but it's probably the hardest part of the whole project to construct. Without the jig, these sharp miters are difficult and potentially dangerous to cut. With the jig, it's quick, easy and as safe as any cut on a table saw.
The jig consists of a 12-15" piece of 2x4 (part A), another piece 8" long (part B), joined by a piece of 3/4" plywood 4-1/2" x 8" (part C), and a 20° wedge about 8" long (part D), cut from another piece of 2x4. You'll also need a piece of 2x4 as a spacer to construct the jig.
Clamp the three 2x4 pieces together with part A on the left, part B on the right and a piece of 2x4 spacer between them so that one end of all three is even. Put the plywood across the top as shown. Align the back edges and drill pilot holes through the plywood into the outside pieces. It helps to draw a line from the front-right corner of the 8" piece to the back corner of the middle spacer piece, like the dashed red line in the illustration. Screw the plywood (part C) to parts A and B, keeping the screws into part B behind that line (since the section of part B in front of that line will be cut off). The spacer piece of 2x4 can be removed.
The wedge can be marked with a protractor or a Handi-Square. If you don't have any other way to mark a 20° angle, you can cut a piece of heavy paper or cardboard that's 3" wide and 8-1/4" long. Draw a line across opposite corners. and cut along that line. That will give you a pattern that's extremely close to 20°. The easiest way I found to cut this diagonal out of 2x4 is to clamp it to a crosscut sled on your table saw. There are other ways such as on a band saw or even with a hand saw. As you can easily see from the pictures, I used some pretty rough scrap wood for my jig. Both of the screw holes in the wedge need to be countersunk, one just a little, but the other one (about half way to the wider end) will have to be fairly deep to let the screw reach into the other block (see picture #4 above)
Make sure that you keep all screws going into part B back far enough that you won't hit them with your saw blade in the next step. The area marked in red on the drawing will be cut off, so any screws from the top or through the wedge cannot go into that area. (I learned the hard way... and wondered why it was so hard to cut - and made sparks.)
Adjust your saw so that you can cut through a 2x4 standing on its edge (3-1/2" blade height). Place the jig assembly with the wedge against your rip fence and the fence adjusted so that the distance from the fence to the blade is just less than to the inside back edge of part A (see picture) and cut off the front part of part B (shown above on the drawing in red). Once this is done, screw a small (1-1/2" x 2" or smaller) piece of wood or rigid plastic to the back edge of part B as shown. This is a stop block to hold the back end of the 2x4 you will be beveling with the jig. It helps keep all of the legs consistent and your cuts flat.
Step 3: Using the Jig
Once you have the jig constructed, you've done the hard part. You need to cut eight pieces 32" long for 30" tall sawhorses. (If you want a different height, multiply your desired finished height by 1.064 to calculate the length of the legs you need.) If you want taller ones, you'll probably also have to get two 10 foot 2x4's to replace two of the 8 foot long ones. If you are using 32" legs, you can cut three of the eight foot (96") pieces into thirds. This will give you nine legs, so you'll have a spare. One of the other 8 foot ones will be cut in half for the two cross pieces, and the last two will be left at full length.
Now you have to use the jig you just made to cut the bevels on one end of each of the legs. Raise the blade so that you can cut through a 2x4 standing on its edge (3-1/2"). Adjust your rip fence so that the distance from the blade to the fence is the same as it was to cut the wedge off the inside (the red piece in the drawing). Place one end of a leg between the 2x4's of the jig and against the stop block you made in the back (closest) end. put a C-clamp towards the front of the jig on the long arm that sticks out (which is the whole reason it sticks out). Holding the right side of the jig (the one with the wedge attached) against the rip fence, push the whole assembly (jig and sawhorse leg) through the saw. When you're finished with that leg take off the clamp, remove that leg and do the same thing to the seven others. The jig makes it easy, safe, and accurate. If you want your sawhorses to stand flat on the bottom, now is the time to cut that 70° bevel. Just remember which way the bevel needs to go - it's embarrassing if you cut it the wrong way and have a sharp point resting on the ground. (I almost did that, but caught myself.)
While your miter fence is set to 70°, it is also time to cut the plywood braces for your sawhorses. Cut one miter on one end of your plywood strip then flip it over so that you will cut trapezoid shapes instead of parallelograms (see drawing). You'll need 8 of these. It's a good idea to pre-drill these 3/4" from the angled edges - that will get you in the middle of the 2x4 legs.
Mark a line across the narrow sides of each leg square to the 20° angled cut, then taper the sides slightly (the part shown in green) with a plane, a rasp, or a sander (take maybe 1/8" off each side) Doing this allows the leg sets to be stacked for storage. The leg pieces are now ready for assembly.
Step 4: Assembling the Legs
When I first made mine, I fumbled around for quite a while, trying to get the legs lined up properly to screw the brackets on. I'd get everything lined up and then it would move just as I tried to screw things together. So I made another fixture to make it easier to get everything lined up for assembly. It was nothing more than an upside-down T made out of some more 2x4's. The crossbar needs to be at least 27" wide (longer than the "spread" of the legs) and the vertical should be at least as tall as the sawhorses will be. I put a screw into each side of the crosspiece 11" from the vertical piece in the center to keep them in the right place (see drawing). Set the bottom of each leg against those stops and the top ends against the vertical piece. Adjust everything so it's even and square. Put one of the plywood braces so that the top of the brace is 3-1/4" from the top of the legs and screw the brace to both legs. Flip the whole thing over and do the same on the other side. Now take that leg assembly off the T-fixture and do it again with your other pairs of legs and braces. You should have two pairs of leg assemblies that each have a pocket in the top that will fit a 2x4 crosspiece. I have found that 4 foot wide sawhorses are the most useful, especially when working with sheet goods like plywood and particle board. If you cut two 4 foot pieces from one of your 2x4's, you will have crosspieces for your two sawhorses. Stand the leg assembly up and put one end of the crosspiece in the space at the top. Put a screw (or drill a hole all the way through and use a bolt, washer and nut) through the set of legs and the crosspiece. That holds them together quite well and still makes them quick and easy to take apart for storage. Without the crosspieces, the legs sets themselves will stack as shown and the crosspieces can be stood up alongside them.
Step 5: Making the Sawhorses Even More Useful
Trying to cut sheet goods such as plywood, paneling, hardboard, or particle board while it's on sawhorses is quite difficult without help. Unless you have a helper to hold up the cut off piece, the weight of the material makes the sheet sag and break before you complete your cut. This generally leaves a jagged edge and may even ruin the material. You can make extra sawhorses and support your plywood in multiple places, but if ground is uneven, that doesn't always work too well and, of course, you need more sawhorses to do that.
By adding a couple 8 foot 2 x 4's you can make your sawhorses work better. To keep the platform relatively flat, notch out half-way through both sawhorse crosspieces and these supports as you can see in the pictures. It's a simple addition that can be done to many wooden sawhorses. You may need help getting a full sheet onto the sawhorses, but from that point, you can work without assistance.
The notches can be cut with a chisel, but I simply marked out the thickness of the 2x4 (which was 1-1/2") 8-12" from the ends on both the sawhorse crossbars and the additional supports (which are nothing but 8 foot long 2x4's), set my table saw blade height to 1-3/4" and cut out the section between them by making multiple passes and moving the stock slightly until a scrap piece of 2x4 fit. For me, it was easiest to notch out the tops of the sawhorse crosspieces and the bottoms of the "table" supports with a handsaw then using a chisel to remove the inside portion. Making the sawhorses this way, you can either use the sawhorses by themselves or with the additional supports for a sheet stock table. They make working on plywood sheets at a construction site much easier, even if the construction site is your back yard. If you are laying out large objects for painting - such as doors - the 8 foot table supports can replace the regular 4 foot sawhorse crossbars to give you two unconnected 8 foot wide sawhorses for painting and drying.
Whether or not you actually make the sawhorses as I've shown or not, I hope this Instructable has given you some ideas to make your life easier. Enjoy making stuff -- and stuff to make stuff.