Replies

1. 
   cadiddlehopper | Jun 28, 2006 11:59pm | #1

   I recently saw dovetailed plywood drawers in factory-made furniture. I wondered why they did it. So, I have to ask: Why do you want to do it? There are other joints which should work much better with plywood while avoiding breakout also. Though it isn't a very good choice for plywood either, glued finger joints should offer better strength. Dovetails provide very little long grain to long grain gluing surfaces in plywood. There are other things to consider with plywood also such as the number of plies & voids. Why don't you tell us more about what you are doing?

   Cadiddlehopper

   
   

   ---

   Edited 6/28/2006 5:01 pm ET by cadiddlehopper

1. 
   Mike&L | Aug 30, 2006 02:01pm | #2

   Well, one of my books on making kitchen cabinets says that IF you use baltic birch or appleply plywood, with no voids, (if)....

   then machine making (router and jig) dovetails make perfect sense, as they look "professional", are actually quite a bit stronger than a dado joint, resist racking and separation, and therefore do a good job of making a long-lasting drawer-front joint.

   So I'm planning to do that with my own kitchen cabinets.

1. 
   cadiddlehopper | Aug 30, 2006 03:03pm | #3

   This discussion goes back a few days, doesn't it? I'm impressed with your serious approach to this problem.I have 3 cabinets with 3 drawers each with plywood sides dadoed into plywood fronts & backs which are approaching 40 years old. There is no looseness in any joint. They have been used daily over this time. They have been moved to 6 houses. The reason for this is probably the superiority of the glues we have these days. I used white or yellow, I can't recall which. Some of the dovetails on our factory-made furniture, which is much newer, are loose. I don't know the importance of durability to you, of course.If appearance is what you are after, then make dovetails in plywood while living by the caveats in your book. I am fairly certain that a dadoed or finger joint which is glued will actually be stronger & more durable in plywood. Analytically, you end up with slightly more long-grain-to-long-grain surface area for gluing. You will need some luck dovetailing the plywood, too. There was so much chipping of the ones I saw in factory drawers that I was not just unimpressed, I was put off by it. You probably should make some prototype joints to get your technique polished to your satisfaction. You might also want to take a look at what factories are doing to their plywood drawers by visiting a furniture store.BTW & out of curiosity: Why not use solid wood & dovetails? LOL!!Cadiddlehopper

1. 
   Mike&L | Aug 30, 2006 04:22pm | #4

   Note to all - I re-read this before I posted it - and I'm pompous here.  Sorry, don't mean to be - too lazy to rewrite it.

   - - - - - - - -

   Well, you make many excellent points - not the least of which is the 40 year test.

   But, no fair bringing up factory made drawers.  The key for a good factory made drawer is that goes together fast, is reasonably foolproof to assemble, and will last a year or two until the owner is ready for a new style breakfront or end table. 

   Will a properly made dado joint outlast a properly made machine dovetail in plywood?  Remember that the long grain, short grain surface argument is a less telling argument in plywood since the long grain glued to is a 32nd of an inch thick and is held in place by a cross-grain glue joint (how plywood is made, after all) to the next layer of ply.   Given that the dado is made with reasonable precision (fits, both pieces are flat, square, etc, remains clamped until the glue drys, and the plywood drawer bottom is glued in, then it should last effectively forever.

   And there's no denying that the finger joint- I'm thinking box joint - will trump both, hands down (I'm full of pun, ... or something).   Mechanically strong, LOTS of glue surface (long grain, short grain).    But it's ugly.

   Finally (that terrible word), all that not withstanding, I actually like the look of apple-ply on a drawer side.    No other defense. 

    

1. 
   oldusty | Aug 30, 2006 05:50pm | #5

   Mike and All ,

                  Dovetails can be made with plywood but,,, the one thing to be warned or careful of is trying a dry fit just to make sure they fit properly. When you knock them apart you may loose some of the plywood on the dovetails , it just happens so take that into consideration so as not to spoil all that work .

              Why not use solid stock , Poplar or some other reasonably priced material ?

                                             dusty

2. 
   cadiddlehopper | Aug 30, 2006 07:10pm | #6

   In a plywood-to-plywood dovetail there is actually very little long-grain-to-long-grain surface to which to apply glue. Nearly all surfaces are at angles to the grain direction, hence little except end grain is available on one side of the joints. Because plywood has two mutually perpendicular grain directions, finger or dado joints provide about equal areas of L-g-2-L-G contact. As to appearance: Finger joints aren't offensive to me. As I said before: You certainly should make some prototype dovetail joints before going into production. You may be perfectly satisfied with the results. But,if appearance is your main objective, solid wood sides & front would enhance appearance even more & provide good, strong dovetail joints.Cadiddlehopper

2. 
   BBTB | Aug 31, 2006 12:45am | #7

   You might have already solved your issue but....

   I have used baltic-birch plywood for some cabinet drawers recently and used dovetail joints to join the box.  I have a leigh dovetail jig that I used.  I clamped some thin scrap stock (maybe 1/4" thick) on both sides of the of the drawer side where I was routing the dovetail with perfect results (make sure the clamps are out of the way of the router bit).  This prevented any blow out on the drawer sides where I was routing. 

   Good luck!

1. 
   Bogart | Aug 31, 2006 02:03pm | #8

   That sounds like the perfect solution to this problem. Gotta love this forum. Thanks Bogart

1. 
   Mike&L | Sep 01, 2006 04:57pm | #9

   Great solution.  Thanks.

1. 
   HWG | Sep 01, 2006 05:27pm | #10

   Mike, I recently made a desk for my wife and for some crazy reason used ply for the drawer sides.  I made it all work, but I sure found myself wishing that I had used solid wood.  In drawers the solid wood looks so much better and you don't have to fight the splintering.  Also, if you have to sand the sides any to get a good fit you don't have to worry about sanding through the thin layer of surface ply like you do with plywood.  What I made will work fine, but I sure wish I had spent a few dollars more and used the proper wood.  It was a lot of time spent on something that does not reflect the efoort that I put into it, because of the use of the plywood.Woody

1. 
   gossamershavings | Nov 24, 2006 06:25am | #11

   anyone worried about the strenght of plywood dovetals should just do this.. The shape of the tails (i assume the tails are on the sides..haha) will prevent the joint pulling apart front to back. the joint can really only come apart one way. To remedy this, flip the drawer upside down, drill a quarter inch hole about 75 percent through or so, and glue in a dowel. trim when dry and pare flush. THAT joint will NEVER come apart in normal use, and unless you are on your back looking up with the drawer open, you will never see it...has worked for me...will last longer than any glue, me thinks,.... good luck...