INCRA Ultra 24 - Manual (Page 15)

1 5
After making your first series of pin cuts,
check the fit with one of the tail boards. If the
tail board doesn’t fit all the way into the pin board,
just measure the distance it protrudes. See Fig. 34.
This is the distance you need to move the INCRA
Stop AWAY from the bit to achieve a flush fit.
FIG. 35
Pins and Tails
TAILS
Tails begin with a
dovetail shaped rabbet.
(half blinds only)
Tail boards are always
cut VERTICALLY,
clamped to the INCRA
Right Angle Fixture.
The first and last cuts
on tail boards are
ALWAYS "open cuts".
This means the edges
are cut away
Pin boards will ALWAYS have
half pins (solid stock) on
the outer edges of the
board
Pin boards are cut
FACE DOWN on the
router table
PINS
PIN BOARD
TAIL BOARD
FIG. 34
Move
INCRA
Stop back
this far to
achieve a
flush fit
You have just completed your first INCRA half blind
dovetail. You'll notice in the first step you set the depth of cut
by making two cuts
7 /
8
" apart. This spacing works well with a
1 /
2
" 14
°
dovetail bit, but larger or smaller diameter bits will
require a different spacing between these two cuts. To help
you determine the proper spacing you'll find a chart on page 3
of the INCRA Master Reference Guide & Template Library.
The chart will give you the proper spacing for the router bit and
template pattern you have selected. You'll also find the proper
spacing listed as "Distance to set depth of cut" under each
template pattern diagram in the back of the INCRA Master
Reference Guide & Template Library. Since different
diameter router bits will also require different rabbet widths, the
INCRA Master Reference Guide & Template Library also
gives this information with each joint pattern.
In Steps 2 and 3, you positioned and used a 1 /
32
" scale to
locate the various cuts for the tail and pin boards. When you
later begin using the joinery templates from the optional
INCRA Master Reference Guide & Template Library, they
will be used in the same way. In fact, you can think of the
joinery templates as “scales” that have had all the marks you
don’t need erased. Just find the center of the stock width you
are using with the router bit, then slide the suggested “center
cut” on the template under the hairline cursor. Each template
has two series of marks, “A” cuts and “B” cuts. Just use one
series for your tail board cuts and the other series for your pins.
Pins or Tails?
Looking at an assembled dovetail, it is
often difficult at first glance to tell which
boards are the pins and which boards
are the tails. They each have dovetail
shaped cuts in them, so what makes
them different and where is each used in
a case construction?
To answer the last question, dovetails
are most often used for one of two
different reasons-beauty or strength.
When used to decorate a piece, most
woodworkers prefer to put the tail boards
on the side of the construction most
visible to the viewer. When used for
strength, the tail boards are placed in
the construction so that they are parallel
to the direction of the force being
applied. In drawer constructions, for
instance, the tail boards are always
placed on the sides parallel to the pull
and push motions involved in opening
and closing. This places the pin boards
on the front and back. Wall hung
cabinets should always be built with the
tail boards on the sides, since once the
cabinet is loaded with weight, the force
is downward. This places the pin boards
on the top and bottom. Once you’ve
determined which sides of your
construction will be pins and which will
be tails, use the illustration and the
information in Fig. 35 to ensure the
proper cuts are made on each.