On 29 Nov 2006 19:04:57 -0800, "
wrote:

Hi all. I'm trying to build a fairly basic tv stand for my first
project. I plan on using 3/4 hardwood plywood for the 5 sides of the
case. Approx. size of the box is 14"x18"x24". I planned on mitred
joints for the top, bottom and sides to avoid the ply showing. Is this
a good idea for plywood? Doesn't seem very sturdy. What other joints
are appropriate for plywood case joinery that would be flush? Also, I
assume I would cover the plys showing from the face of the box with
regular hardwood. This would necessarily be 3/4" strips, is this
correct? Whats the best way to join the hardwood to the exposed plys?
Are these parts of plywood suitable for glueing or even some more
advanced joint. Am I stupid for using plywood? It just seems difficult
to find real wood in the larger width dimensions to make case sides.
Most planks I've looked at are no more than 12" wide. Thanks for
listening to these stupid questions. I'm trying to teach myself with
only books, since I don't personally know any woodworkers. Thanks, Peter

Hi Peter-

They're not particularly stupid questions, everyone was new at this at
one time.

Here's another idea for you based on the tools you've got-

Case sides are often made from hardwood ply for just the reason you've
noted. They also expand and contract less with changes in humidity.
But to avoid a cheap IKEA-style particle board look, it's nice to use
floating panels in frames. This was developed (as I understand it) to
allow glued-up solid wood panels to expand and contract without
breaking the wood around them, but it ends up being a pleasing look
that is often used in furniture even though the use of plywood reduces
the need for it.

I'll try to decribe how to make them with what you've got, and
hopefully that will be enough to help you visualise what I'm
describing- I'm sure you've seen it before somewhere, it's very
common.

Get your plywood, and some hardwood planks- the planks can be narrow,
or even pre-cut to a specific width, like 1.5 or 2" (which may be the
way to go, as you said you do not have a tablesaw.) Many lumberyards
will rip them for you from wider stock for a fairly inexpensive hourly
rate.

Once you've got your planks, you can start making the frame. Get a
straight router bit that is the same width as your plywood is thick
(and with this application, your plywood can be a thin as 1/4"- the
mechanical joints are in the frame). Use your router to route a
groove (called a dado) in the edge of your planks. If you want them
centered on the plank, there is an easy way to do that- draw a line on
your router's baseplate that crosses directly over the center of the
bit, and drill two holes that are the same distance from the center on
either side. Put a pin in each hole, set the router on the edge of
the plank, and then turn it so that one pin is touching each face of
the plank. Plunge your bit about 1/4" deep, then route along the
length, keeping the pins touching the faces of the plank. This will
keep the bit centered, and prevent the router from wandering
off-course and making a wavy line. If you want a dado deeper than
1/4", just keep making more passes, removing a little more material
each time- don't try to do it all in one shot.

Once all your frame pieces are dadoed, you need to decide what kind of
joinery you're going to use to hold it together. Miters are easy with
that radial arm saw of yours, but are not that strong. Simple butt
joints are pretty weak as well, but have the benefit of being really
easy to make. Arguably the best joint to use is a mortise and tenon,
but they take a bit of practice to get right. Basically, you just
make a square hole in the edge of one piece, and a square peg on the
end of the other, then slide them together. Other things to try out
are a half-lap joint, which looks like a butt joint or a mortise and
tenon joint, but glues the two faces together and is much stronger
than a butt joint- but not as strong as a mortise and tenon. You
could also make a splined miter, where you cut the miter, then make a
dado on each of the angled cuts, and glue in a thin strip of wood-
that will make a miter joint much tougher, or sink screws into the
joint and cover the heads with a short piece of dowel glued in place.
It's your first project, so try not to make it too complicated right
off the bat- just do what seems right to you, and you'll discover what
you like quickly enough.

Once you've got that figured out, cut the frame pieces out of the
planks that you made the dadoes in. Make sure that when the pieces of
the frame are assembled, the dado will be facing in towards the
center. Put the frame together unglued, and measure the distance from
the bottom of your dado to the bottom of the dado across from it, then
subtract a sixteenth. Do that for both dimentions, then cut your
plywood to that size. Glue up three pieces of the frame, slide in the
plywood, and then glue in the fourth. Getting a regular tie-down
rachet strap like you'd use on a trailer makes clamping frames very
easy- put your glue on all the joints, (note- you should not be
putting glue in the dadoes that the panel sits in, so that if the
panel expands or contracts, it does not break the frame) assemble by
hand, then wrap the strap around the outside and ratchet it down.
This works particularly well with miter joints.

Do that for each of your sides, then you can glue the sides together.
Here, a simple butt joint will be fine- because it is not *really* a
butt joint- it's an edge-grain to face-grain joint that will be
stronger than the wood itself once glued.

The top is a little different- you can use plywood, of course, and
then glue hardwood all the way around, with miters in the corners.
When you attach it, allow for wood movement- an easy way to do this is
with L-brackets that attach to the inside of the frame walls, and
under the bottom of the table with screws. Make sure that the
brackets have a slot rather than a simple hole on the leg that is
attaching to the top.

Hope this helps- I know it's a lot to read through, but woodworking
can be a complicated business until you've got a few projects under
your belt.

Have fun!