I had planned to do this with a project but recently read that plywood
won't be strong enough. Has anyone tried this? What part of the
joint won't be strong enough?
I'm building a small cabinet with a shelf that will have about 40-50
lbs of weight on it. Because of the design, I can't have any
fasteners coming in from the outside. I don't want to have plugged
holes either. Initially I planned to use dado's to hold the shelf. I
later decided that sliding dovetails would help hold the sides
together too. The top of the cabinet is a hinged lid so it won't
provide any support in holding the top together. The front and back
of the cabinet will have a face frame so the back can't provide
lateral stability either.
I'm using 3/4" Red Oak Plywood but who knows what the center is made
of. I haven't counted the ply's (if that makes a difference).
Any advice is appreciated!
You can cut the joint, though if you are using a router on the ends of
the shelf scribe the veneer prior to crosscutting with the DT cutter to
prevent breakout. As for stability, one shelf will help but on its own I
agree with the other posters.
Seems to me that if you dovetail a long pin on the edge of a sheet of
plywood, you are effectively reducing the support of the joint to a tenon
the thickness of the base of the pin. The plies that form the top and bottom
of the pin will have been separated from the rest of the sheet and would now
be held to the sheet only through the glue that bonds the plies themselves.
If you mentally exaggerate the movement of the joint under racking and
deflection stress, you can visualize that the stress on the "orphaned" plies
will only weaken their bond to one another: any support from the wider
portions of the pin would contribute to the strength of the joint only as
long as the fibers and glue in them remained microscopically intact.
Furthermore, if you imagine that the wider portions of the pin have become
completely separated, the joint now actually consists of a flat-sided tenon
housed in a long "tail", supported only by the inner, narrow edge of the
I'm an amateur hobbyist, so I sure can't claim any certainty, but it seems
to me that the strongest joint would be a good old dado, which would
maximize the glued surface area, minimize any compromise of the plies, and
give the most wood-to-wood anti-racking contact.
It sounds as if you are making a stereo cabinet: how about adding hardwood
cleats under the shelves and/or corner braces at the back of the cabinet?
The same criticism can be made of a solid wood sliding dovetail in
straight grained wood. Since modern glues are reputed to be stronger
than the wood.....
Strength is not the issue, stiffness is. Without fasteners there is only
the glue holding the sides together. The OP does not want fasteners yet
wishes some stiffness, a sliding DT joint is thus the joint of choice.
Debate is then over exactly how much stiffness one such joint at either
end will impart. The choice of joint is correct.
Slightly different scenario:
I was going to do this very thing (dovetails w/plywood) but for a
different purpose. I'm trying to suspend a shelf within a cabinet
(say for a VCR) and was planning on using dovetails to act in concert
with the glue to hold the shelf in place (suspended). i.s. sliding
(pins?) dovetails on the underside of the shelf above, who's
counterparts (tails?) would be the side pieces of the suspended shelf.
That way you have a bit of a structural joint just in case...
Ya suppose this might not be a good idea? Alternatives? Alternatives
that don't involved hardware? Or, is there hardware I can hide (kinda
like a bed rail doohickey)?
On 11 Aug 2003 06:36:12 -0700, firstname.lastname@example.org (todd1814) wrote:
I think I see what you mean. If you want to do this without hardware
then your choice of joint is correct. If your stock is thick enough and
the pin angle is right it should also be strong enough.
OK - thanx.
3/4" thick but I'm not sure of the angle that the router bit has.
Would closer to vertical (angle) be better?
On Wed, 13 Aug 2003 19:46:44 GMT, email@example.com (Peter
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