One of the things I was not completely happy with on the DW746 table saw was the stock DeWalt rip fence. It does not have any attachment holes or fittings for sacrificial fence faces, and because of its curved top and low profile does not lend itself to attachment of featherboards or jigs. I had seen and admired the Biesemeyer fence, with its two parallel faces; such a structure is easily used to clamp on featherboards and jigs, and does not require re-adjustment to use the opposite face when needed.
I decided I wanted a two-faced fence like the "Biese", and started out by cutting two faces, 4"H x 34"L and fastened them to the DeWalt beam, in essentially the same fashion as the stock fence face, that is, by clamping one side to the other with bolts through the beam. I found, however, that the DeWalt beam is not square enough to hold the faces parallel and perpendicular to the saw table at the same time, so they would have to be somehow fastened together. The DeWalt beam clamp also seems to be a source of distortion of the beam; this distortion is readily visible in the photo below.
After a lot of consideration of ways to do this, including looking at Christopher Merrill's BIGAFENCE, I came to the conclusion that a secondary beam to which the faces could be bolted was the way to proceed. This gave the advantage that, if the beam didn't turn out correctly, I could easily and inexpensively make another, and the relatively expensive faces, being independent and removeable, would not be glued into a botched permanent structure.
I had plenty of 1/2" MDF left over from a router-table enclosure and the Full Cabinet Extension project, so used this to make a beam, 1-7/8"H x 3"W to suit the fence faces. It consists of two side-pieces 1-7/8"W x 34"L, with 1/2"W x 1/4"Depth rabbets along each edge, and two top pieces, 2-1/2"W x 34"L glued into the rabbets, giving a strong, stable beam structure.
Five holes are drilled through the top and bottom plates, for access to the beam clamp screws and the
beam-tail-skid screws. Five 1/4-20 threaded inserts are installed using epoxy-adhesive, equally spaced
along the center line of each beam-face; the fence face-plates attach to these using 1/4-20 x 1-1/4" FH
Phillips machine screws, counter-sunk just below the surface of the face-plates.
I am planning to add more inserts to the structure as needed, for the attachment of special jigs.
The left-hand face has three inserts on its inside face, opposite their respective mounting holes in
the DeWalt metal beam; the right-hand face has 3/8" through holes in the same positions, and these are
counter-bored on the inside of the face just enough to provide clearance for the beam-clamping washers.
The new fence assembly is clamped to the DeWalt beam in virtually the same way as the stock fence, by
tightening the left-face against the beam via a clamp and washer on the right side of the beam. In this
case, the clamp is a 3-1/2" 1/4-20 socket-head cap screw passed through from the right side, passing
through the washers and the metal beam, and into the threaded inserts provided. The right fence-face
rests on the cap-screw heads. Thus, no modification is required to the stock DeWalt equipment.
Note, that the only reason the fence developed this way was because I had already made the faces; a stable, effective, and inexpensive fence with non-removeable faces can be made similar to this, but as a unitized, glued-up unit, using 3/4" MDF for both faces and structure, constructed similarly to the BIGAFENCE. Whichever style of fence you may decide to build, the length and height of the fence facing and construction materials used is up to you.