Greetings and Salutations....

On Tue, 23 Mar 2004 00:12:29 GMT, Micheal R. Frichette
wrote:

Okay I am getting ready to make some sliding dovetails, or at least an
attempt at them. ( I am destructing a secretary desk modified for my
use as a humidor, and it calls for sliding dovetails.] Has anyone had
the pleasure of doing a sliding dovetail that is about 24 inches long?
Any suggestions on getting this done properly would be great. I do
have a Bench Dog 150 router table but am not sure that I could keep
the piece (shelf) steady enough to make a good clean route. The shelf
is 3/4 inch stock by about 36 long, by 24 inch wide, glued up of black
walnut. Is there a simple jig that can be made, or is it one
necessary?

Well, I hope you can take the router out of the table, as this
is one of those cases where it is easier to move the router than it is
to move the stock.
In the spirit of True Woodworking...I would suggest getting
either the Porter Cable or Leigh (I think) jig with the sliding
dovetail attachment. That will be the quickest way to get to cutting
the joints.
Alternatively, you can make the jigs you need. It will
require a bit of testing and fitting, but, can go ok. use 3/4"
plywood (decent quality stuff) for the jigs.
1) you will need a jig to cut the dovetail on the end of the
board. This consists of an "L" shaped platform with legs about 6"
long. Re-enforce the joint with triangular Glue blocks for
strength and stability. One leg is used to clamp the jig to the
stock. ON the OTHER leg, attach a guide rail such that
when the router base slides along it, the dovetail
bit will cut the OUTSIDE edge of the dovetail on the end
of the stock. (I *really* hope that makes sense...).
To use the jig...clamp it to the stock, with the top edge
flush with the edge to be tailed. Set the depth of the bit to
the appropriate amount. Fire up the router and cut one side of the
joint. Swap the jig to the OTHER side of the stock, and cut the
OTHER side of the dovetail.
Now...we run into the problem of the socket. There is more
than one way to do this, but, I am going to describe the SIMPLIST
way...or at least the way that requires the simplist jig. This
kind of assumes that your dovetail bit is the width
of the tail...although it is quite possible to do it with one
that is a smaller width.
First off...get a good, known straight edge. Clamp it
to the surface that is to receive the socket, so that the dove
tail bit will cut the FAR side of the socket in the correct place.
Make VERY sure that the straight edge is perpendicular to the
side of the piece. Cut the dovetail slot. (the "far" side of
the socket is the edge AWAY from the straight edge).
If your bit is the same width as the dovetail you made
on the end of the board, you are, essentially, done. If it is
smaller, you will have to carefully move the straight edge over
away from the slot you just cut enough to cut the near side
of the socket. Now...if you want to make it easier to get this
puppy together...kick out one end of the straight edge about
a 32d or so further away from the slot when you move it. This
will taper one side of the slot slightly but not so much that
it will become sloppy.
Of course...when gluing up this thing, remember to only
put glue on the last couple of inches of the socket that the
tail slides into, and, on the last couple of inches of tail
to slide into the socket. If you glue the entire slot, the
likelyhood of ending up with a side stuck halfway into the slot
goes up exponentially.

Then again maybe I am not ready for this joint but just getting very
prepared.

Thanks for your assistance.

Mikie :-)
The only way to prepare is to do it. Of course, I would
STRONGLY suggest that you get some poplar and make a few test
joints first...so you are comfortable with the process and understand
what is going on. One never wants to practice on the REAL project.
Remember..the project we see Norm build on the show is the THIRD
one he has built (which is one reason it goes so smoothly).
Dave Mundt