On Mar 19, 7:20*pm, "Lew Hodgett" wrote:
"sam" wrote:
I want to take a 30" length of 4" wide board and put a slot all the
way through the board about 4" long. the centerline of the slot will
be *3/4 of and inch from the edge of the board. Where do I put the
fence? Do I hold the board above the router and slowly lower it in
position, or do I drill my 5/16 hole first into the board and fit
the router bit into the hole, bringing my fence up to the board?
Will I get a true straight clean slot this way, with no wobble?

What you want to do is the functional equivalent of cutting a mortise
using a router and a straight bit.

IMHO, it is not possible to safely accomplish this operation using a
fixed base router, router table with a fence.

You need a plunge router and jigs that duplicate the functional
equivalent of cutting a mortise.

Do a Google for "mortise jig" to get and idea of an approach to
solving your problem safely.

Lew

Better yet, look up "Multi-router" ala David Marks. Not only is this
setup safe, accurate and easy - it's about the coolest router
accessory I've ever seen. Might be a bit expensive, but it sure would
be nice to have in the shop!