From: bennett@adobe.com(Bennett Leeds)
Subject: Re: Delta contractor's saw as a router table
Reply-To: bennett@adobe.com
Organization: Adobe Systems Incorporated
Distribution: na
Date: Wed, 23 Dec 1992 00:34:49 GMT

G. Paul Houtz writes
> rdc@world.std.com (Ralph D Clifford) writes:
> >     I am in the process of building a new router table....
> >     One option I am thinking about would be to mount the router in the
> >table board on my Delta contractor's saw with unifence.
> >     Has anyone done this and, if so, do you have any recommendations for
> >or against?
> ------------
> 
>    Yep.  I did it.  Works good.  Get Patrick Spielman's book "Router Jigs
>    and Techniques" and read about his "ultimate router table"  I used the
>    layout for his inser plate for mine.   It tells you what materials are
>    safe.

There's been some debate over which material is best for the insert plate
part of a router table. Some say polycarbonate (like Lexan or Tuffak) is
best because of its resistance to shattering. Others say that acrylic
(like plexiglass) is best because it's stiffer and won't sag under the
weight of a heavy 3 HP router. Lately, there's been a number of manufacturers
selling phenolic resin plates, saying they're the best of all (however,
they're not transparent). At least one manufacturer, Excaliber, sells a
pricey metal insert plate.

Another area of concern is plate thickness. The thicker the plate, the
stiffer it is, but also the more depth of cut is lost. Since the collet
on some routers doesn't even reach the factory sub-base, adding another
3/8" to the base compounds the matter even more. In some cases, it may
be better to go with a stiffer material in a 1/4" thickness.


>    Also:  Get some allen screws and a matching tap and drill and tap 4 holes
>    in your insert plate, and then screw the allen scres into those holes.
>    Use them to level the plat in the table, otherwise your work will hang
>    up on the edges constantly.  Don't bother with shimming, you will just
>    be wasting your time.

It is a good idea to have some means to adjust making the insert plate
level with the table surface. However, using screws at the corners of
the plate may increase the amount that the plate sags under load. Unlike
a tablesaw insert plate, a router plate supports quite a load. The usual
rabbet around the edges is good in that it supports the plate completely
around its circumference. When you add the leveling screws, you move the
load out to the corners, which are further away increasing the torque
on the plate.

An interesting alternative, which I haven't yet tried, is to use something
like Woodhaven's levelers. These are plastic gizmos that replace the
rabbeted ledge in the table's hole. Since they're long and located in the
center of each side, the load is spread out over a larger area than a screw
head and is also located closer to the router's load.

One other thing I've found to be important is that the plate fit the
table hole snugly. If the plate can move sideways in the table, the distance
of the bit from the fence will vary, leading to poor results. If the fit
is too snug, you either can't get the insert plate in, or it buldges up
when forced in. My recommendation is to make the plate slightly oversize
and then use a handplane or scraper to trim it to fit.

- Bennett Leeds
bennett@adobe.com