Kitchen Table Construction Questions - Wide boards?

[alex grams]

I am going to design a kitchen table for my wife (a round breakfast table, ~4' diameter. I am going to make it out of solid cherry (most likely some 1x6 butted side by side). My concern is the bowing of the wood once the table is assembled. I anticipate adding two pieces of 1x2 on the underside of the table that will run perpendicular to the main table, and this should help prevent any bowing of the table in general.

But my other concern is with any wood over 4" in width, there can be bowing of the individual pieces of wood. Is this a legitimate concern, and if so, what are some ways to address this, as well as prevent any overall bowing between the pieces of lumber (is my first solution the appropriate solution?).

Thanks in advance.

[Jim Becker]

I work exclusively with wide lumber, especially for table tops. I want as few boards as possible. For the next project I'm doing that is table oriented, my boards are 13" wide rough. If you choose your stock carefully, let it acclimate before and after milling and then assemble it carefully using techniques that take into account wood movement, you will not have any real issues. For something that large, I also typically use 5/4 material for the table top which comes out to about 1" after milling/finishing.

Your perpendicular support boards are not uncommon for this kind of project. But you cannot just glue and screw them to the bottom of your top. Screws only and all but the two or so fasteners toward the middle of the table need to be in slots so that the table top can expand and contract seasonally. That keeps it flat, but doesn't cause cracking. Again...it's how you build it that counts!

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BTW, I'm going to move this thread to General Woodworking as it's really more about technique than rote design. You'll get more commentary that way.

[alex grams]

Jim,
Thanks for the advice. Are you suggesting to only screw the supports at certain points? I can't understand exactly what you are suggesting. I understand the need for allowing the wood to move perpendicular to its grain.

Please clarify if you can, and thanks again for the advice.

[George Bregar]

Jim,
Thanks for the advice. Are you suggesting to only screw the supports at certain points? I can't understand exactly what you are suggesting. I understand the need for allowing the wood to move perpendicular to its grain.

Please clarify if you can, and thanks again for the advice. The center screw can be tight, but the outer screw need to be slotted to allow for movement (se pic).

Wider boards will be more prone to cupping, alternate the grain orientation so that each board the natural cup is opposite. Cherry is almost always flat sawn, look at the end grain..it will be "u" shaped. One up, next down.

Also, I would use different width boards and an odd number. An odd number eliminates a center glue line...the eye will be drawn to it. Common widths are boring, and again draws the eye to the fact that it is a glue up.

HTH, and good luck on the table. have fun.

[alex grams]

Thanks for the clarification George/Jim.

[john lawson]

A woodworking teacher of mine said there was a special place in h _ _ _ for anyone would intentionally made a board narrower than it had to be.
:):):)


john lawson

[George Bregar]

Thanks for the clarification George/Jim. YW, hope this wasn't condescending. Not sure what experience you have.

[alex grams]

Nah, I grew up working in my grandfathers cabinet shot and did a lot of cabinets for schools/stores/offices and such. I just got my first house this year and some room to do some work and get some tools. I do a lot of other work around the house other than woodworking (tile/plumbing/electrical), but what I most enjoy is woodworking (it is my therapy and relief from work). I have good experience in building and design, but am wanting to move more into skilled craftsmanship instead of just simple production.


On a side note, I miss all of the tools from the family cabinet shop :( 5hp sliding table saw, pocket hole press, 40" drum sander, and the cyclone system for the building that made piles of sawdust 10' high from its bin in the back...

[George Bregar]

A woodworking teacher of mine said there was a special place in h _ _ _ for anyone would intentionally made a board narrower than it had to be.
:):):)


john lawson Guess the issue is what determines "had to be".

[Sam Yerardi]

I think most agree it's amazing how much force is generated by the movement of wood due to water/moisture. I don't have vast experience on table tops. I've read a lot and even the top pros (Frid, Becksvoort, etc.) all have different opinions about tops. I've used wide and narrow boards both. Alternating and non-alternating grain. I think sometimes the best you can do is to try to not add additional offending things to the potential for failure. Strapping the boards across grain is a good idea as long as you provide for expansion and contraction (as has been pointed out here) . For a long time I had the incorrect assumption that a cross-piece if sized right would hold any top flat. My personal experience has been if the top is going to move regardless of wide or narrow boards it is going to move. The degree it moves I think has a lot to do with the size of the boards, how the grain is oriented, etc. I hope others jump in here and tell me whether or not I'm full of beans but that's the impression I've gotten both from my experience and from reading.

[Paul Simmel]

If you alternate the end grain (wide or narrow) and the boards cup, your top is going to get waves. Alternating does not stop cupping if the wood is determined to do so.

Milling the stock, leaving it slightly oversized, then stickering for awhile (to let it move again) is your best bet. Don’t stack too high or weight down. You want it to move on its own. Once your stock has moved again, mill it again.

If you can’t do that, don’t alternate the end grain… match it. It’s much better to have all the wood pulling in one direction. Your cross members can keep it flat. Your cross members will not stop waves, (alternating ripples) however.

[George Bregar]

If you alternate the end grain (wide or narrow) and the boards cup, your top is going to get waves. Alternating does not stop cupping if the wood is determined to do so. Nothing will stop it.


Milling the stock, leaving it slightly oversized, then stickering for awhile (to let it move again) is your best bet. Don’t stack too high or weight down. You want it to move on its own. Once your stock has moved again, mill it again. This is good practice no doubt, but is moot in regard to gluing up panels


If you can’t do that, don’t alternate the end grain… match it. It’s much better to have all the wood pulling in one direction. Your cross members can keep it flat. Your cross members will not stop waves, (alternating ripples) however. :confused:

[Al Killian]

There many things coase issues with glue ups, two boards with different moisture will be a bigger problem then wide boards vs narrow boards. I have boards that are 15" wide that are still flat and have boards that are 4" wide that are warped. The type of wood and how it was cut from the log will determine how likely it is to twist or warp.

[Al Willits]

"""""""
assemble it carefully using techniques that take into account wood movement
""""""""

I was with ya Jim till that point, are you talking about attaching the top to the rest of the table or ??

Al

[Jim Becker]

I pretty much never even look at the ends of the boards to see how they are oriented. I choose stock for something like a table top purely on color and grain matching with the ultimate goal of any joints actually disappearing, even when using wide boards. If I can get the top to look like a single wide board, I will. Interestingly and on this same vein, the top on our kitchen table, which is 2" thick teak and from Viet Nam back in the early 1960s (Professor Dr. SWMBO's 'rents worked for "the government"....;) ), the 52" diameter surface is made from a single board that was cut in half and rejoined. There is one glue line halfway across... :D

[john lawson]

I do exactly as Jim said, I match color and grain with objective of making the table top look as much as possible like one piece of wood. This is particularly true on a wood like cherry or walnut where you might have sapwood on one side. For me, that is much more important than trying to alternate the boards to prevent warping.

As someone said earlier, the wood will do what it wants to do no matter what you do. I have found that if the wood is normalized to the shop and I do a good job with the jointer, then hold the table top to the apron while allowing it to move, that I do not have warping of the top. If fact, the fastening of top will, in most cases, pull a slight warp out of the top.

john lawson

[Josiah Bartlett]

And, I don't think anybody mentioned this yet, but make sure to finish both sides of the table top with exactly the same finish and # of coats, so it absorbs and releases moisture at an even rate. Also, you could store the boards in the final location of the table for a few days before milling and final glueup so they are acclimated to the environment.

[Michael McCoy]

I do exactly as Jim said, I match color and grain with objective of making the table top look as much as possible like one piece of wood. This is particularly true on a wood like cherry or walnut where you might have sapwood on one side. For me, that is much more important than trying to alternate the boards to prevent warping.

As someone said earlier, the wood will do what it wants to do no matter what you do. I have found that if the wood is normalized to the shop and I do a good job with the jointer, then hold the table top to the apron while allowing it to move, that I do not have warping of the top. If fact, the fastening of top will, in most cases, pull a slight warp out of the top.

john lawson

Ditto. I won't waste the time to write what I was already going to since John already did it. :) I think a lot of people are under the impression that you have to start machining the wood as soon as possible but I was taught a long time ago that wood only has so much radical movement. If you let it do it's thing, it won't be radical in the long run.

[Paul Simmel]

George,

I do exactly as Jim does too.

If the boards are going to cup (no matter why), it would be better to have one continuous cup... like a big smile rather than a bunch of frowns mixed in. With one big potential smile, the whole piece could be pulled down flat with the cross members.

Cupping wood is no good any way you look at it. But if it is going to cup, better to have a table top without (or minimized) rippling. Alternating end grain will not prevent the pieces from cupping. It wont even minimize it.

Hope this helps.