what router bit would you need to make horizontal wooden siding?

Answer 1

What profile are you looking for? If you are trying to make Dutch Lap siding, You will need a T&G set, and a round bead. Plank siding is just plain sawed wood, plained on one side. Tapered siding is plain sawed, or quarter sawed, or even split out of a log. Neither Plank, nor Tapered requires a router.
There are other styles of siding, plus other archetectural ornaments, such as corbels, dentil, and brackets. The router could be useful in the manufacture of some of these.

Answer 2

I doubt that the rust is smart enough to know how to penetrate at an equal level across the table. Never seen a router bit for metal, and trying to set up a jig for "perfection" would be hard. The proper way to do this, if you want a machined finish, is to remove the table and take it to a machine shop. They can put it on a surface grinder and do perfect surfaces.

Answer 3

You would be better-off getting a shaper with the head shapes that were recommended. Even with a router table it is hard to control the passage of the wood past the router cutters. The shaper makes it easy and keeps you from ruining a long piece of wood.

Answer 4

1