One of the easiest ways to cut tenons is on the table saw with a tenoning jig. A number of companies sell commercial tenoning jigs, which are designed to ride in the table saw's mitre slot and to hold the tenon board vertically. The entire assembly is pushed forward past the saw blade, cutting the tenon. However, you don't have to have a commercial tenoning jig when a homemade table saw tenon cutter works just as well.
Measure the width and height of your table saw's fence, using a tape measure.
Cut a 2.5 by 15 cm (1 by 6 inch) board into four lengths of 32.5 cm (13 inches) and another at 30 cm (12 inches) long, using a hand saw.
Set up the table saw, and rip three of the four 32.5 cm (13 inch) boards to the width of the table saw fence, as determined in Step 1. Rip the fourth 32.5 cm (13 inch) board to a width equalling the height of the table saw fence plus 5.6 cm (2 1/4 inches). Rip the 30 cm (12 inch) board to a width of 7.5 cm (3 inches).
Stack the three matching 32.5 cm (13 inch) boards together so they are flush on all four sides. Glue and screw the boards together to form a block.
Turn the block on its side and attach the fourth 32.5 cm (13 inch) board to the side of the block, with the edge of the board flush with the top edge of the block. Attach with glue and screws.
Move the table saw's fence so that it is to the right of the saw blade. Position the block on top of the fence, with the protruding board hanging down over the right side of the fence.
Place the 32.5 by 30 cm (13 by 12 inch) piece of plywood vertically against the left side of the fence with a edge flat on the table. Align the front edge of the plywood with the front edge of the block. Attach with glue and screws. Check to see that the jig glides forward and backward along the fence smoothly, with no play in the movement.
Stand the 7.5 cm (3 inch) wide board vertically against the left side of the plywood, with the edge of the board flush with the edge of the plywood closest to your body. This board will become the fence. Check that the fence board is square to the table with a framing square, and attach to the plywood with deck screws. Do not place any screws in the bottom 8.7 cm (3 1/2 inches) of the board, as these could interfere with the saw blade when the jig is in use.
To use the jig, clamp the tenon board in place vertically flat against the plywood, with the edge firmly against the jig's fence board. Adjust the position of the table saw's fence left or right so that the blade aligns perfectly with the cut mark on the tenon board. Turn on the saw blade, and ease the entire jig forward until the shoulder cut is completed. Flip the board over in the jig to complete the shoulder cut on the opposite side of the tenon board. You can then make the cheek cuts to remove the waste with your table saw and a mitre gauge.
When working with power tools, always wear appropriate safety gear, including safety glasses.