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 We
asked Paul Ruhlmann, the co-inventor of the Veritas? Tenon Cutter, to
show and tell us how to make a garden obelisk. His challenging design
is a four-sided ladder with sloped rungs and topped with an optional oblong
centerpiece. The obelisk is built by making two individual ladders, which
are then joined together with additional rungs. It is made of peeled maple
and has a 15" square footprint with 6' long posts tapering to leave a
space wide enough to accept a decorative centerpiece.
- Select four upright posts
(about 1-1/2" diameter and 6' to 7' long) of the material of your choice.
Cut a 1" dia. tenon, 1-1/2" long, on the bottom of each post. Divide
your posts into pairs. Mark your posts so you will know which is which
later on (e.g., FL, FR, BL, BR for front left, front right, back left,
back right, respectively).
- Select material suitable
for twenty 3/4" to 1" dia. rungs. (The length of each rung will be determined
as you build each ladder side.)
- Mark the approximate location
of each of the five rungs on your pair of posts that will make up the
front ladder. Stagger the location of the lowest hole in each post in
order to obtain sloped rungs. Our obelisk has the lower rung about 8"
from the bottom of one post and about 13" from the bottom of the other
post in the pair.
- Set one of the posts in
a vise and drill five 5/8" dia. mortises, about 3/4" deep. Note that
each hole should be drilled at a constant angle. (Paul Ruhlmann's video,
Making Rustic Furniture, provides details on how to position
posts and drill mortises at the correct angle.) Drill the holes in the
other post, remembering to maintain the same angle but in the opposite
direction.
- Cut a 15" long bottom rung
and an 8" long top rung. Put a 5/8" dia. tenon, about 3/4" long, on
each end and dry fit into the mortises.
- Measure and cut the middle
rungs to size, about 1-1/2" longer than the space into which each is
to fit (to account for the tenons), and put a 5/8" dia. tenon, about
3/4" long, on each end and dry fit into the mortises.
- Repeat steps 3 to 6 to make
the back ladder.
- Stand the front and back
ladders up with the post ends equally spaced, and lean them toward each
other until the tops contact in order to mark the location of the rungs
that will make up the obelisk's sides. Drill mortises and cut rungs
in the same manner as was done to make a ladder.
- Glue the rungs with a slow-setting
epoxy. Start by gluing the front ladder rungs, proceed to glue the back
ladder rungs, and then glue the sides.
- Reinforce joints by cross
pinning the rungs with 1/8" dowel.
- Make your centerpiece. (This
piece can be an interesting-looking object, or it can be carved or turned.)
Counterbore a screw through each top post to secure the centerpiece.
Cover the screw holes with plugs.
- Apply a suitable outdoor
finish of your choice, such as polymerized tung oil, or paint the obelisk
with milk paint.
- Cut four pieces of 1" I.D.
pipe about 8" long. Drill a 1/4" hole in the sidewall, about 1" from
an end.
- Place a pipe on each tenon,
with the cross-hole oriented toward the tenon. Secure pipes to the tenons
with a screw into each hole.
- Drive the pipes into the
ground, leaving about 2" of pipe exposed. The steel pipes will keep
the obelisk posts from being in contact with wet soil.
J.M. & P.R.
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