Replies

1. 
   wellis | Jul 02, 2007 09:18pm | #1

   Wood movement is proportionate to overall size so that if you see a 2% increase in 1 inch it is only .02", but on a 48" wide table top the movement is almost an inch.  Accordingly, rabbets or dados are unlikely to cause any problem.  Drawers and bread board ends are the greatest victims of moisture.

   Education is the process of making mistakes and then identifying them.  If you don't do anything, you won't make any mistakes, but you won't learn either.

   Just Do It!

   Bill

2. 
   byhammerandhand | Jul 02, 2007 09:50pm | #2

   Are you an engineer? It seems like you're over analyzing. Yes, a shelf will expand and contract. How much? A small percentage of 0.75" Generally not enough to worry about. Just my opinion.

   In the past month, I've repaired a number of new drawers where the bottoms were solid wood. Grain oriented left to right -- good. Slot in the back where screw held bottom to back -- good.

   Only problem is they forgot to tell the assembly line
   1. Do not glue the bottoms into the grooves.
   2. Do not run the flat head screw (in the back slot) halfway down into the depth of the bottom.

   Every one of them had one or more 1/4" splits in the bottom. It was quite nice that you could open the drawer and still see the floor.

   This is the type of problem you need to avoid.

3. 
   hammer1 | Jul 03, 2007 06:24am | #3

   Repeat after me, it's only woodworking, it's only woodworking, it's only woodworking...

   Beat it to fit / Paint it to match

1. 
   byhammerandhand | Jul 03, 2007 04:17pm | #4

   Gosh, this reminds me of a story. A furniture store that I work for sent me to a consumer's home to repair an easel. It seems the painting they were putting on it was too heavy and the adjustable bottom stop wasn't holding the rail in place and it kept sliding down.I proceed to look at its to weigh some options and the husband says, "I don't care if you just stick in a piece of wood and screw it in place to stop the slide; we're never going to change it."OK, I think, so I get ready to cut a small stop block with a handsaw, and he says, "Oh, you can use my shop if you want." He takes me and my little piece of wood downstairs to the most elaborate shop I've ever seen, it would make Norm green with envy. (Did I say this guy was former CEO of a large engineering company when it got bought out? Did I mention later he showed me his completed projects, all six of them?) He pulls out a dial caliper and measures the slide to the nearest thousandth. Then uses the calipers to set the Beismeier fence on the Unisaw. Rips a small piece for me, I thank him and run back upstairs to the easel. Slide the piece in position and there's an 1/8" gap because of the flex in the mounting rails.

4. 
   chairmannz | Jul 05, 2007 01:39pm | #5

   Hi BigFrank,

   Just do it the way you think will look good and that it will stay together.

   There is no sure way working with timber it works even when we are sleeping.

   I made a table with solid top for my son and its 1 mtr width (3'4') and is contracts 10mm (3/8") between summer and winter the breadboard ends are a good reverence point to see the difference.

   I have made lots of mistakes and learn from it, its something that you can not avoid when working with wood.

   Greetings Bernhard.

5. 
   AdamCherubini | Jul 05, 2007 02:18pm | #6

   Dear Frank,

   Yes. A dado is a good choice for that sort of joint as is a rabbet for the other. Movement cross grain is fine with all these joints. The problem you can encounter is warping of the individual pieces. So the trick becomes the attachments.

   In the 18th c, furniture makers had a few standard ways of dealing with the sort of joints you are talking about. The top and bottom of your book case would either be nailed or dovetailed to the sides. Either way, you want something to restrain the sides from cupping or twisting. I like to put heart side out and dovetail. The back edge of the sides was typically rabbeted for a nailed on back. The grain direction of the back varies. It seems to me to be best to have the backers horizontal so they hold teh sides together. Discreet boards (ship lapped?) and small nails make the cross grain joinery not so bad.

   The shelves would run loose in dadoes, but a front trim piece was sometimes added and that piece was dovetailed to the carcass (and the shelf glued to it from behind.) If there were many shelves, sometimes only one or two would be dovetailed. These sliding dovetails supported the sides in the front to stop them from warping or bowing.

   My advice is to learn more about 18th c construction techniques. It'll give you a little more confidence in your own designs. I recommend Jeff Greene's book "American Furniture of the 18th century" (Taunton Press). Its a wonderful book, and in my opinion a must have for every woodworker.

   Good Luck,

   Adam

1. 
   BigFrank | Jul 05, 2007 08:27pm | #7

   Thanks guys - especially Adam,
   That was exactly the kind of info I was looking for.I'm essentially making a service for my espresso machine and grinder - the top surface is about 20x20 so its a fairly large area. if you look at the design from the front it would look like this: |__________________|
   | |
   | | 5.5 inches tall
   -------------------- 20 inches wide and deepfrom the side:

   ------------------
   |
   | |
   --------------------There will be a drawer inside for holding espresso machine parts etc.
   i got to thinking about this - and I'm second guessing it again - it seems like the grain on the sides should run the back to front and the top should run left to right (so it wont be in the same direction as the sides). seems like a dado would *not* work in this case. I may try it anyhow to see what will happen, but i really dont think this is going to work out. Frank