On 11/1/2013 10:18 AM, Swingman wrote:
set up a fence on one edge of a piece of plywood and use spacers to
provide the distance between the flutes.

I had originally envisioned a custom base for the router with a fence to
ride along (one) edge of the work. I'd set the fence to center the first
flute, then add a spacer to the fence for the two flutes that flank the
center one (doing one from either side to ensure they'd be symmetrical
about the center line). Then I'd add a second spacer of the same
thickness and repeat on each side.

The Rockler jig has two advantages as I see it.

1. It has two fences, preventing me from losing contact between the work
and the single fence I had in mind. That seems like a good idea.

2. All of the routing would be done from one edge, meaning that one set
of "end stops" would be used for all of the flutes, ensuring the ends of
the flutes would line up.

The disadvantage is mostly the cost, for an item I'd be unlikely to use
very often. I could try to build something like it, but I wonder about
my ability to make it accurate enough to get the flutes symmetrical and
evenly-spaced without doing them from either side and with spacers.

I suppose I could still do it my way, but add a (movable) secondary
fence for the second side. Then I'd just have to make sure the router
was centered on the custom base (in the "length" direction) so the end
stops would correctly from either side.

What material would you make the fences (and spacers) out of? Something
smooth, I imagine, not ply. Hardwood scraps? Plastic? Aluminum angle?

As always, if any of this seems ignorant, it is.