New and Improved table design

OK, I adjusted the table dimensions to severely minimize sag, but still want to go for that stretcherless, trestleless, "minimalist" look. Using red oak, will edge join (maybe w/ biscuits, maybe not) 16 3"x1"x72" planks for a 72x48x1 top. If I join these right and true, the top itself should be sufficiently sturdy of it's own accord for dining table purposes (the wood is about 80 pounds, I tested 280 pounds on the sagulator and still get less than 'visible' sag, with legs at the very corners. That seemed like not enough sag to be anywhere near failure, ihmo. Anything really wrong with that logic?
Even so, if we could assume for a moment I could design a such a top, I would like to place the legs about 6" from each corner. Each leg will be 3 1x3's laminated together. Since I'm going for no stretchers or trestles, I have the following idea for joining the legs, which is kind of a dado/through tenon hybrid:
top view: long side x-section: short side x-section: (long side) |-----------| |------------| |-------------- | | | | | |---| |---| | | | -------|| ||------- ---|| ||------ |----+++++++--- || || || || | +++++++ -------|| ||------- ---|| ||------ | +++++++ |---| |---| | | |----+++++++--- | | | | | | | | | | |-------------- | |
After laminating the legs into the 3x3 dimension, I'll make 2 1"x1" dadoes, 1" from the top. The table top plank which this leg is attached to will actually be 3 planks, one between the legs, and one between each of the legs and the end of the top. So, the top will actually be assembled with 2 of the planks being shorter, so it appears to have 4 notches. The legs will go into these notches, with one dado facing the end of the short plank. Then the "really" short plank will go with it's end into the other dado, and it's edges matching the surrounding 2 planks.
If I match the edges well enough and use good glue technique, I would think the legs would be pretty darn sturdy for a dining table. Does this sound reasonable?
The final issue is movement - namely the top planks 'wanting' to expand/contract (tangentially) as much as .10" more than the legs (radially) if they are both plainsawn. I don't know if I can negate these or not.Even if the glue holds, it might cause a split in the top plank somewhere. Applying enough tensile force to stretch a 3" plank by .10" seems like enough to split it to me, but that's based on totally uninformed guessing, not hard calculations - which I'd be interested in learning how to do if someone could point me to a good book with the relevent engineering education in it. Also, the legs will tangentially expand/contract against the dado joints, but with this design, that movement would only be about .03" unrestricted, as it's 1" of wood thickness in this plane as opposed to 3", so I "think" this wouldn't be a problem.
-Chance Casey
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Perhaps it is me but this has to be one of the most boring posts I have ever read . You seem to think people understand what you are talking about . The old addage a picture is worth a thousand words seems in order you could either post pictures or plans on either the woodworking binaries newsgroup or perhaps a website....mjh
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"Chance Casey" < snipped-for-privacy@hotmail.com> wrote in message
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Give the kid a chance, okay? Maybe the table will rack onto his mother-in-law. Tom >"Chance Casey"

Someday, it'll all be over....
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Chance,
Your ASCII art isn't coming thru. Make a drawing or take pictures of your mock-up and post them to a.b.p.w along with your questions and I'm sure you'll get some better responses.
Bob S.
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snipped-for-privacy@hotmail.com (Chance Casey) wrote:

My guess is that without an apron or stretchers, or at least corner blocks, the table will be pretty wobbly. Looking at the web page you posted, am I correct that the legs will stand proud of the surface of the table? Interesting design idea, and I like if for other uses. But for a dining table (I assume that is the use for a 72x48 table)? What happens the first time someone puts a pitcher or dish of hot food or their glass half-way on the leg?

I'd GUESS no problem with expansion. The only cross-grain situations you have (IF I interpreted the drawing correctly) are thickness of top versus length of leg (width of dado) and thickness of wood between the dados versus length of the top. Similar amounts of cross-grain in every M&T joint.
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(Chance Casey) wrote:

Yes, 1" proud - and simply to beef up the joint. My wife also pointed out that it could be functionally problematic for dining. So this may be bad all the way around. Thanks for the advice on it being wobbly. That's something I really don't have a feel for yet, and it seems like a subjective judgement. It was also my main concern. I guess if I really want this 'top and leg ONLY' look, I'm resigned to getting a large piece of steel custom made. That's probably not going to be cheap.
-chance
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On 7 Apr 2004 18:46:17 -0700, snipped-for-privacy@hotmail.com (Chance Casey) wrote:

You could probably make a stiffening frame of wood that was in from the edges and wouldn't be visible from ordinary viewing heights. Children palying on the floor will see it, but they will have other concerns and probably won't complain.
Rodney Myrvaagnes J36 Gjo/a
The meme for blind faith secures its own perpetuation by the simple unconscious expedient of discouraging rational inquiry.     - Richard Dawkins, "Viruses of the Mind"
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