TONGUE & DADO JOINT
On our front porch,we used tongue and dado the rip fence,and making a pass over the blade
joints to join the cladding that surrounds the (Fig. 2).To ensure that the dado is a consistent
4x4 posts.As you can see in the Photo below, depth, I mounted a featherboard to my rip
there s a tongue on one piece that s formed by fence to hold the workpiece down on the
cutting a rabbet in the edge.This tongue fits table. Cut the dado in all four pieces before
into a dado cut in a mating piece.These inter- turning your attention to the rabbets.
locking parts form a strong mechanical joint. Rabbet Setup Once the grooves are
Plus,the large glue surface of the joint provides completed, the next step is to cut a rabbet in
LOCKING
additional strength. the opposite edge of each piece to form the
RABBET
Tongue & Dado Basics  The main goal tongue.You can use the same width dado blade
#/4"
when creating this joint is to have the tongue as for the groove to make the rabbet. Only Tongue
fit into the dado with a friction fit  not too this time,attach an auxiliary fence to the table
tight, but not so loose that the mating pieces saw s rip fence,and set the dado blade so it just
#/8"
can move around. Also, the pieces that are grazes the side of this fence (Fig. 3). Here, the
joined together should fit flush with each position of the fence in relation to the blade
other on the outside. determines the length of the tongue, which
Dado Setup  To accomplish these two should match the depth of the mating dado
3
#/8" #/8"
things, I start by cutting the dado. (For the (in our case, / "). Groove
8
porch project on page 38,it s a 3/ "-wide dado, The other critical dimension here is the
8
3
/ " deep.) For that size of dado, it s easy depth of cut,as it determines the thickness of the } TTThe interlocking parts of the
8
enough to mount the proper size of dado tongue. To get a good fit, run a test piece tongue and dado form a sound
blade in the table saw. through the blade. Then test the fit of this mechanical joint and have a
The critical thing, however, is positioning tongue in one of the dadoes you ve already cut. large glue surface for strength.
the rip fence to cut this dado.That s because Adjust the depth of cut accordingly, sneaking
the fence determines the location of the inside up on a perfect fit.
shoulder of the groove.To get a flush-fitting Make the Rabbet  Once you
joint, this shoulder has to be set in from the have achieved a nice fit
edge of the workpiece a distance that matches between the tongue and
the thickness of the stock.The easiest way to the dado, proceed with
do this is to use a scrap piece of the cladding cutting the rabbets in all
material as a thickness gauge for setting the rip four pieces (Fig. 3).
fence (see Fig. 1 below). Again, use a feather-
Get in the Groove  With the fence set, board to hold the work-
cutting the dado is as easy as setting the work- piece down on the table
piece face down on the table,butting it against saw during the cut.
#/8"-long
1 2 3
tongue
Aux.
Rip Rip
Scrap Piece
Fence
Fence Fence
#/8" Dado
of Cladding
Blade
#/8" Dado
Blade
Workpiece
{ TTUse a scrap piece of { TTHolding the workpiece { TTAfter attaching an auxil-
cladding as a thickness firmly against the fence, cut iary fence, rabbet the edge
gauge to set the rip fence. the dado in a single pass. to form the mating tongue.