The fence that comes with your table saw is fine for ripping wood where the wood is lying flat on the table. Where it is not so good is when you have to stand a piece of wood against the fence to make a cut into the end of it, You may need this to cut raised panels or cut a dado into the edge for joining 2 pieces. These fences are just not tall enough to make this cut safely as it puts your fingers too close to the spinning blade.

This auxiliary fence extends the height of your fence and allows you to make these cuts more safely because your fingers will be much further away from the blade.

Being a woodworker with all of his fingers, I am willing to do what I need to keep it that way.

Note on links: Links are provided to take you to Amazon.com where you can buy the supplies listed or just to see what a typical tool looks like. If you like these instructables and wish to support the making of them, all you need to do is to click on one of the links and purchase anything on Amazon. Thank you in advance for your support.

Step 1: Materials and Tools

Materials (sized for my fence)

Melamine board (25 1/2" x 7 1/2" x 1") for the main fence
Plywood (5" x 2 5/8" x 1/2") for the vertical supports
Plywood (5" x 3 1/4" x 1/2") for the horizontal supports
Glue
Wood Screws

Tools

Step 2: Making the Main Fence

Cut the Melamine to size (remember your measurements may differ)
Set up your table saw with dado blades to cut a 1/2" dado, 1/2" deep.
Set your fence so that the distance of the dado from the edge is equal to the distance from the top of your fence to the table surface MINUS 1/8". This is really important because this will prevent the auxiliary fence from dragging on the table surface.
Make the dado cut the whole length of the fence.

Step 3: Adding the Horizontal Supports

Cut the horizontal supports to size. Remember the thickness of your fence may be different and you need to adjust the dimensions here too.
Glue and clamp these support pieces into the dado of the aux. fence at either end making sure they are 90 degrees to the fence.

Step 4: Completing the Assembly

Cut the vertical support pieces to size. The height should be equal to the distance of the dado to the edge on the aux. fence.
The following steps are important.
Remove your fence from your saw.
Clamp the aux. fence and the vertical support pieces to the sides of your fence, see picture.
Also, Clamp the horizontal support pieces to the top of your fence.
Pre-drill 3 screw holes in each horizontal support piece and into the top of the vertical piece.
Then screw (and glue?) them together (and let dry)
Your fence is now complete.

Clamping to your fence is critical if you want a tight fit. If your fence is extruded aluminum like mine, you can also drill a hole in the top of horizontal support pieces for bolts where the head slides in from the edge of the fence. This way you can secure the aux. fence your table saw fence.