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Any advice on joining some 12/4 red oak lumber together for a table top? I can use biscuits or dowels, but would like to know what works best. I have never joined anything so thick.

Table will be 80" x 40", and the lumber I have is 12/4 and 10" wide.

Thanks in advance,
Ernie
 

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For something that thick I might try a spline joint just to help line up those thick slabs. With a sline joint you'll need to stay away from the edges so it won't be seen after glue up.
 

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Discussion Starter #6
ok, disregard. Moisture content. What should it be? This wood has been air drying since hurricaine Katrina.
 

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Why not build your table like a door and use stave core with 1/4" face veneers? It would be a lot more stable. If it were quarter-sawn white oak, that would be a different story but air-dried red oak may move on you quite a bit.

You can make stave core by using finger-jointed pine, rip it to strips then glue it back together so the joints don't line up.

You could even book match the face veneers and/or sequence them in some interesting way if you want that look since you will be resawing out of just a couple boards.
 

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What is an "MC" and what happened to the maple table?

Those "breadboard ends" sound very complicated. Are they worth the effort?

George

"MC" is percentage of moisture content. The breadboard ends on that table should have been done differently. Ordinarily, if done correctly, they are worth the effort.








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I think this might be the maple table they're referring to

What is an "MC" and what happened to the maple table?

Those "breadboard ends" sound very complicated. Are they worth the effort?

George
George - I think that they might be referring to my table. You can see what happened here: http://www.woodworkingtalk.com/f2/table-disaster-ideas-22380/ And I'm glad to have learned the proper name of the "end caps" (what I have been calling them). I glued and screwed them all the way across. I thought the wood was dry enough that it wouldn't expand / contract to the level that it did, and the drying basically ripped the table in half. The integrity of the table is okay due to the absurd strength of the substructure (I tend to over-engineer), but I'm REALLY bummed about how it looks now. I might take the easy way out and fill it with something...... Once I figure out the best thing to use...
 

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BTW - my table was roughly 9/4 when planed and "dried." For what it's worth. I biscuited it every 15 inches or so just to add a bit of torsional strength to the table. I also used pocket-hole screws, but another member (woodnthings) told me I shouldn't have done that because it put uneven pressure on the joing (makes perfect sense ------ in retrospect). But I would definitely biscuit it -- it certainly can't hurt.
 

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George - I think that they might be referring to my table. You can see what happened here: http://www.woodworkingtalk.com/f2/table-disaster-ideas-22380/ And I'm glad to have learned the proper name of the "end caps" (what I have been calling them). I glued and screwed them all the way across. I thought the wood was dry enough that it wouldn't expand / contract to the level that it did, and the drying basically ripped the table in half. The integrity of the table is okay due to the absurd strength of the substructure (I tend to over-engineer), but I'm REALLY bummed about how it looks now. I might take the easy way out and fill it with something...... Once I figure out the best thing to use...
Yes I was refering to your table, only because I did'nt have a picture of my 2" thick pine french farm table I built that did exactly the same thing as yours. OUCH:furious: That's when I found out about breadboard ends and their purpose. Oh yeah and moiture content, even though the wood was reclaimed it still moved a lot. I do apoligize if I offended you by using your table for example.
 

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Yes I was refering to your table, only because I did'nt have a picture of my 2" thick pine french farm table I built that did exactly the same thing as yours. OUCH:furious: That's when I found out about breadboard ends and their purpose.
Thanks JMC, and the article you posted is fantastic. I've added the link to my favorites. It does seem like a lot of work, and while I didn't originally intend to use breadboard ends, when I was looking at tables online to get design ideas, I realized that the table simply wouldn't look finished without them.
 

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Yes I was refering to your table, only because I did'nt have a picture of my 2" thick pine french farm table I built that did exactly the same thing as yours. OUCH:furious: That's when I found out about breadboard ends and their purpose. Oh yeah and moiture content, even though the wood was reclaimed it still moved a lot. I do apoligize if I offended you by using your table for example.
...........and you absolutely DID NOT offend me. I appreciate all of the advice I've received through this forum, and if we can't learn from each other's mistakes and successes, what's the point! I'll see if I can't drum up a few more mistakes that people can learn from. Like a poster I saw one time of the rusted hull of an old ship half sunk in sand:
"It may be that your sole purpose in life is simply to serve as a warning to others"

I love that poster :)
 

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If ALL of the oak for this table top has been air drying for around 5 years, and it was stickered and stacked properly (dead level, equaly spaced and sized stickers, weighted on top or ratchet strapped tight, covered with a roof and shaded from direct sunlight) than whatever the MC is it should be consistent throughout all the boards which to my mind is more important than the actual number.

If you don't have a moisture meter you should get one; decent ones start around $120 and it is cheap insurance. I use a lingo mini d and it works great, cheap on amazon. if you are about to spend your time wrestling 12/4 x10" oak boards you want to know the table is going to have a good chance at staying flat!

If you have or get a meter, your boards should be around 12% MC, give or take a point or two for your location (your area's relative humidity).

if the MC is good and the boards came off the stack nice and flat, you should be good to go by just edge jointing accurately and glueing up. You want to get this right the first time so check your edges with a reliable square at a few points along the length and make sure you are at exactly 90º.

cauls across the width will help keep you flat during glue up. you could make some curved cauls, which i find useful for big table top glue ups. If you search the interweb you will find advice on making those.

Biscuits will not add any strength to the top but will help line the boards up and keep everything together during glue up. If you have a biscuit jointer you may as well pop a few #20's in there just to keep everything aligned.

You may want to glue the top up in two stages. join two boards at a time, then join the two glue ups together. That way you are only working with one glue line at a time and you can really focus on a perfect joint. :thumbsup:

out of curiosity, what is the base design for this beast?
 

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Discussion Starter #16
MrBent-

Thanks for the informative reply. I will post the design as soon as my boss (read wife) approves the final design.

In terms of the curved cauls, I tried to search for them without luck. I am having trouble picturing it. Could you post a link?

Thanks again in advance.
 

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If you run your boards on the jointer, you just need to be sure to flip the boards so that any slight variation from 90 will be compensated for. Flipping the boards insures you will be exactly flat if you clamp it right.

Don't know if that makes sense, just think about it this way: you could be out of square a full 5 degrees on all your edges but if you flip the boards so that one board has a positive bevel and the next has a negative bevel, you will be able to stay exactly flat across the full width.
 

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Unless you want a table that thick and heavy why don't you resaw the red oak to 1.5" or so. It would reduce the weight of the table significantly and you would have material left over for something else. It would also make it easier to construct the table. If you want the look of a thick table you can get the thickness with the aprons, assuming you have aprons. Just a suggestion, good luck.
 

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Discussion Starter #19
My initial plan was to have a thinner top, but the lumber I was able to get was 3" thick. I will plane it to 10/4, but that is still very thick. I do not have the means to resaw it, unless someone can recommend someone here near Hattiesburg, Mississippi that I could pay to do it.

I have a good jointer, and will follow your suggestions about alternating faces so that if it is not perfectly 90 degrees they will still match up.

I have a question on the breadboard ends: how much should I enlongate the holes in the tenon? Also, I assume that the elongation should allow the table to grow or shrink in width, not length?

Thanks in advance for helping a newbie.
 

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In terms of the curved cauls, I tried to search for them without luck. I am having trouble picturing it. Could you post a link?

Thanks again in advance.
curved cauls are sold commercially as a "bowclamp", but something similar can be made in the shop easily. mine are made from 3"x3" oak and maple (salvaged from pallets), about 38" - 42" long.
begin by squaring up your stock. i introduce a slight curve to one edge with a jack plane. I start about 3" from the end, planing towards that end, and with each stroke I move back a little till i get to the middle. do the same on the other side. the result is that the ends of the caul wind up around 1/16" to 1/8" lower than the middle. experiment to get the right amount of curve. I label the curved side with a marker and cover it in clear packing tape so glue doesn't stick. when clamping a panel or table top, place the cauls' curved side against the work, running across the glue up. one clamp at each end pulls the curved edge straight, which applies pressure in the middle.
 
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