After you have removed as much material as you can without the router
falling into the groove that you are making, cut a scrap of wood the same
thickness as what you are removing and stick this piece to the free side of
the bottom of your router with double sided tape. Now you have the support
that you need and it will follow your moves across the rest of that wide
groove. Of course, it is necessary to have a good router bit that makes a
clean smooth flat bottomed cut for this to work properly. If you can't get a
smooth bottom cut from your router bit, then you can't use this method and
you need to make a temporary wide base for your router to bridge the 4" cut.

--
Charley



"Prometheus" wrote in message
...
On Thu, 08 Feb 2007 01:26:24 GMT, "ilaboo"
wrote:

very new to this very dangerous tool--have about 1/2 hour use with it and
did 1000 hours of damage!!

I have to route out a 3/8" deep grove apx 4" by 18 "

problem I am having is after the first few inches the router is now only
resting on 1/2 the platform and it rocks forward and does n asty
things--i
hve larned that you have tto set up guides with this thingh

is ther some sort of attachment that would fit on the base of the router
that would act like a footing and is adjustible so i dont have to keep
foolin with placing guides?

The idea of making your own sub-base is a good one- you can use
whatever you have on hand that is thin enough. just remove the
exisiting base from your router, lay it on your
plywood/hardboard/plexiglass/etc. and use that as a guide to mark
where you need to drill your holes.

*However* that is not truly necessary. With a little practice, you
should be able to route a good recess with half the base on the wood.
Make sure as much of the base as possible is on the unrouted wood, and
one of the handles is over the unrouted wood as well. Start in the
center, and work out in a spiral pattern. Place a little downward
pressure on the handle on the unrouted side and make sure that the
handle over the recess is being guided only- you don't want any
downward pressure on it at all. When you get to the edges, place
another board of the same thickness next to one you're routing.