These sawhorses are extremely strong and easy to make. After reviewing a number of sawhorse plans online I was disappointed with how complex most of the plans were. These are quick and cheap to build. They can carry hundreds of pounds and do not wobble.

TOOLS:
Table Saw
Mitre Saw

Any of these tools can be used to notch the 2x4:
Hand saw, reciprocating saw, hammer and chisel, etc.

MATERIALS (for two sawhorses):
One 8' 2X6
Four 8' 2X4s (three full 2x4s and some scraps over 10 inches will do)

Step 1: Instructions (Part One-Makin' the Pieces)

Create the components in the image. Use a 17 degree angle on the mitre saw and the table saw for all the angle cuts.

To create the top piece (top left of pic):
Set your table saw to a 17 degree angle and run the 2X6 through to make a trapezoid. The base of the trapezoid should measure
5 1/2". Cut this piece in half to make the two tops to your sawhorses.

To create the trapezoidal support piece(top right of pic):
Make sure your mitre box is set to a 17 degree angle.
Cut four trapezoidal pieces out of 2x4 such that they have a 10" base. There should be four in total--two for each sawhorse.

To create the legs (lower portion of picture):
Make sure your mitre box is set to a 17 degree angle.

1- Cut Legs to length
Cut eight 30 1/2" long pieces out of 2x4s. These should be parallelograms in profile and will form the 4 legs of each sawhorse.

2- Notch Legs
On four of the legs notch the upper right piece out of the 2x4. Measure down 5" from the top of the leg and notch out a 1" thick piece of the 2x4. Notching deeper will compromise the horizontal wobble strength of the sawhorse. I notched these by setting my mitre box depth and making multiple 17 degree slices an inch deep in the top 5" of the legs--I removed the remaining chunks of wood on the table saw and did the bottom portion with a hammer and chisel. You may want to use a hand saw or reciprocating saw if you prefer.
Repeat this process with the four other legs, except notch out the upper left portion of these.

Step 2: Instructions (Part Two-- Screw It Together)

Screw the pieces together as shown in the picture using long, strong screws.

Tips:
Make sure the trapezoidal supports are seated in the base of the notches in the legs. This will insure the legs sit solidly on the ground.
1. Screw one side of the trapezoidal supports into a leg.
2. Lay this leg flat on the ground and place the top piece in place vertically to make sure your adjacent leg spacing is correct. Otherwise you may need to notch the top piece to fit it in or conversely it will not fit snuggly.
3. After creating both sets of legs, assemble the saw horse and screw the top piece in place (both into the legs and the trapezoidal support pieces).

You may want to sand the underside of the top piece to avoid splinters.