How To Dado A Large Beam...
Saturday, July 25th, 2009
My wife bought
a hammock for my daughter during a cruise to the
Caribbean. Back in New Hampshire it would have been
easy to hang; just throw a couple screw eyes in 2
large oak trees and swing away. Yea, right,
wishful thinking in Peyton, Colorado. So, I decided
to build my daughter a hammock arbor.
Each post for
this arbor would be approximately 5" square and
there would have 2 dadoes near the top and on
opposite sides to provide a shoulder to support the 2 rafters.
I could layout these dadoes, make repeated passes
with a circular saw and then clean up the dadoes
with a sharp chisel or I could plow them out with a
router. Hmmm? My freehand router skills are OK but
not sufficient for the tight joints that I demand.
So I made a router jig...
This router jig
(Figure 1, 2 & 3) was made with very stable Baltic
Birch plywood and features one fixed beam and one
moveable beam to accommodate routing dadoes of
varying widths. Also, the design features a fixed
fence and moveable fence to clamp and route several
pieces at once. Replaceable sacrificial pieces
of wood are screwed to the face of each fence to
protect the Baltic Birch plywood. This design
allows for one clamp to securely hold to jig to the
wood from underneath and not interfere with the
The beams were
clamped together and the dadoes were defined (Figure
4). Next, 1/8" was added to these outer dimensions
to compensate for the distance between the edge of
the router bit and router collar (Figure 5).
The router jig was then attached to the beams with a
single clamp (Figure 6). Note that the fixed beam
was aligned to the outer mark for routing.
When routing it
is best to set the jig to a narrow width, route,
move the jig, route, and so forth until the desired
width is achieved (Figure 7). This approach merely
allows the router to rest on both beams which
results in a cleaner cut and safer operation. When
the routing is completed remove the jig and note
that the original dado width was achieved (Figure
The edges and
ends of the beams were chamfered with a router and
the beams were sanded and considered completed
(Figure 9 & 10).
Large pieces of
wood cannot be pushed thru the blade of a table saw
and are often too large for even my Dewalt 14"
radial arm saw. This router jig is very
flexible and allows you to safely route narrow or
wide dadoes in single or multiple pieces of wood
safely and effectively.
If you have any
questions or comments about this blog entry please
do not hesitate to
send me an e-mail. Thanks and be
safe when working with tools!!!