Replies

1. 
   WillGeorge | Jan 30, 2005 05:06pm | #1

   Just me.. If the wood is really nice just use some bow ties in the cracks to keep them manageable. I like the look.. Some don't. Just me..

2. 
   JohnWW | Jan 30, 2005 11:40pm | #2

   Tom,

   I can't quite figure out the construction of the table from your description, but a quick calculation shows that you top will shrink more than an 1/8 inch in width for every 1% change in moisture in the wood.  If you live in a climate that has humid summers and dry winters indoors, the top will change in width more than an inch between winter and summer.  It is also quite possible that the top will cup or twist with changes in the weather.

   The fault usually isn't in the glue, if the glue joints don't fail, the wood will crack to relieve the stress, basically something has to give. 

   I'd suggest getting the Lee Valley "Wood Movement Reference Guide" or the book "Understanding Wood" to get an education about what is happening.  After that you need to learn some of the design details that furniture makers use to deal with wood movement.

   That said, there isn't a lot you can do to control the movement of such a massive piece of wood, you basically allow the top to do what it wants and design the rest of the table to adjust to that movement.

   John W.  

1. 
   Trezona | Jan 31, 2005 03:55am | #3

   I appreciate your comments on how much the wood will move and will obtain and review the references you mention. I have successfully removed the ends and one corner piece from each end without damage. The question is how to proceed now. Would it be best to bolt the ends on? I live in Oregon. Its rainy all the time from October through April. Obviously the end pieces are at their greatest length now, which is about 1/16 to 3/32 longer than when I did the glue up in Sept. If I re-size the end pieces to fit now, they will gap upon shrinkage for the shortest period of the year--correct? How would you connect the ends and corners? Getting rid of the ends and corners is an option I don't like.

1. 
   Rich14 | Jan 31, 2005 04:36am | #4

   Tom,Can you post a drawing of the table design? It's not clear just how you have constructed this behemouth.Anything you attach to the ends of the table as a "cap' to the width of the wood either has to move with it or allowance must be made for the differences in movement between the two different grain orientations. The tangential wood movement in the width of the top vs the (almost nil) longitudinal movement in the length of the end piece (if I understand your design) are irresistable forces. The wood or any fasteners are not immoveable objects.You need to take a look at the general design of a "breadboard" table top. The end caps of any such construction, whether attached by bolts, screws or M&T joints must have elongated holes or mortises to accomodate the seasonal variation.And yes, at different times of the year, the main table top and the end piece will have a visible difference in size or gap. It's a hallmark of all such design.Rich

1. 
   Trezona | Jan 31, 2005 08:35am | #5

   I obtained the wood 5 yrs ago. It was cut from tree in 1985. I placed on stickers on the concrete floor of my garage at that time while my shop was undergoing construction. It remained exposed to outside humidity. I started work on the table last March. I moved it into my shop and allowed it to acclimate for 4 months at 60 degrees. I did the glue up in August. That means the wood had the opportunity to dry over 5-6 months at the shop temp. When the ends fractured off they were about 1/16 to 3/32 too long for the slot they were in. That means the main body of the table was still drying and lost dimension relative to the end pieces (which are longitudinally oriented), despite the fact it is the most humid time of the year here. How much more shrinkage should I expect. My (tentative) plan at this point is to bolt the end pieces on so as to allow them to move as the main body of the table shrinks and expands with the yearly humidity change. Sound ok? The wood has now been in my shop for 10 months. Should it not be as dry as possible at this point?

1. 
   Rich14 | Jan 31, 2005 10:08am | #6

   Tom,You are misunderstanding a basic fact about wood, its hydroscopic nature, and a basic principle about wood furniture construction.Wood must be dried from its green state in order to be useful as lumber. Once it has been kiln dried or air dried to an acceptable moisture content (7-10%), it can be worked. But that moisture content is a range and is by no means a "final" or fixed condition.Once dried to lumber condition, wood then constantly gives up moisture or absorbes moisture from the atmosphere as it tries to reach an equilibrium with atmospheric humidity changes. The moisture content of a "dried" board may vary between 3%-25% as atmospheric humidity varies between near zero and 80% (not unusual, for instance, for a home in the midwest, heated in winter and open to the air of a sultry August day). Here's a link about wood Equilibrium Moisture Content and atmospheric Humidity:http://www.csgnetwork.com/emctablecalc.htmlAs it absorbs and releases moisture, it swells and shrinks. It does this month by month, year in, year out. It moves the most in a direction tangential to the tree's growth rings (across the width of flat sawn boards). Somewhat less in a direction radial to the growth ( across the width of quartyer sawn lumber). And almost not at all in the length wise direction of all lumber.Here's a good reference with a graphic showing how lumber changes dimension relative to it's orientaion within the log.http://www.fpl.fs.fed.us/rwu/rwu4714/shrinkage_of_wood_faq.htmlHere's another link to Rockler's "Shrinkulator". With other useful information.http://www.woodbin.com/calcs/shrinkulator.htmThere is nothing you can do to stop this movement. You can only build to compensate for it. Workers who build furniture of solid wood who do not have an understanding of these issues are destined to watch their work destroy itself.Do a Google search for "wood shrinkage" and "equilibrium moisture content." Better yet, get a copy of Bruce Hoadley's, "Understanding Wood." This book is a must for anyone who wants to build anything of solid wood. Read it and you will understand exactly what's happening to your table.And as I suggested before, examine a description of a "breadboard" table to see how wood movement is acommodated in such a design to give you insight as to how you may need to rethink your joinery. There are lots of sources for such plans. Here's one back issue of FWW with such a tablehttp://www.taunton.com/store/pages/fw_toc_141.aspAlso "Practical Design, Solutions and Strategies," Taunton Press discusses many issues and a comprehensive discussion of breadboard ends starting on page 84. Again, how about a drawing of your construction?Rich

2. 
   macalex | Jan 31, 2005 11:48am | #7

   All the above is sound advice. If you want a technical solution, you'll have to post a sketch or provide a better explanation. This forum will have the definitive answer, given anough information!

   MalcolmNew Zealand | New Thinking

3. 
   cherryjohn | Feb 02, 2005 12:29am | #15

   **applauds**.......never heard it explained so well in such a short passage.  It had me totally absorbed.....( so to speak)Wicked Decent Woodworks

   Rochester NH

   " If the women dont find you handsome, they should at least find you handy........yessa!"

3. 
   notDusty | Jan 31, 2005 06:21pm | #8

                 Tom ,

     Rich14 gave you a tremendous amount of vital information , all applicable to your  table design. If I understand you correctly you have attached a border or edge around and on the end grain of the table , correct ?  It sounded like the top is maybe 3" thick ? if that is correct then perhaps you will need to remove the end borders and recut or trim , normally an apron / skirt or a framework will be under a solid top such as this . As has been suggested this under mounted frame should not be glued , but be fashioned to allow the seasonal movement of the top . The seasonal changing of the moisture content that Rich14 refers to can be called the RH factor or relative humidity . Even though a board has been KD its MC will change as the climate changes . Wood can be a very unforgiving medium and stubborn as well , it will do as it wants to and all we can do is design to allow movement . The thicker the lumber the longer it takes to dry , the more movement we can expect . Without seeing the table the advice seems to lean towards removing any wood that is trapping the end grain.

                         good   luck              dusty

1. 
   Trezona | Feb 01, 2005 06:04am | #9

   Better yet I will photograph the table and post the pic. Thanks for your help.

1. 
   Trezona | Feb 01, 2005 06:41am | #10

   Here is a pic of the table end. The corner to the left remains attached.

   
1. 
   notDusty | Feb 01, 2005 08:57am | #11

               Tom ,

       O.K. sit down , take a few deep breaths relax . This is a very nice looking piece of wood , I see the theme of the sap wood border you have worked out . On paper it looks and works great , but in reality you have entrapped  the end grain . That slab is going to move and nothing you can do will stop it . One possible method to correct this would be to cut the end border so the grain is oriented in the same direction as the slab . This would mean gluing short pieces side by side to create the border , but unfortunately you will lose the sap wood . At this late stage of the game I would remove the applied borders and trim and shape the ends of the slab perhaps to the same shape you now have. Except without the border . Sorry I can not come up with a way to continue your plan as started . You tried to defy mother nature , and she won .

                                dusty

2. 
   Rich14 | Feb 01, 2005 09:04am | #12

   OK Tom,Sorry but it's a classic example of complete lack of familiarity with wood movement. That is not meant to make you feel bad. It's just a statement of fact.I have nothing to add that I haven't already said. In fact, I wasn't completely sure of the type of construction involved when I made my suggestions about the information you need to learn. Now there is no question.Get Bruce Hoadley's book. Examine the techiques used in breadboard table construction. In addition to my link of an example of a breadboard, there was another one posted today on the forum:http://forums.taunton.com/tp-knots/messagesRich

1. 
   Rich14 | Feb 01, 2005 09:07am | #13

   Sorry,That link went to the wrong message.Look for "Breadboard techniques?" today under General Discussion.https://www.taunton.com/store/shoppingcart/ssl/tplus.asp?GoToOnSuccess=/store/shoppingcart/online_selection_validation.aspRich

   Edited 2/1/2005 1:08 am ET by Rich14

3. 
   TTed | Feb 01, 2005 09:35pm | #14

   Hi Tom:Sorry to see you in such a jam. I would try two things:First, a modified breadboard: for the end piece, cut a set of floating tenons. I would guess about 0.5" thick, about 4" wide and about 6" long. You'll then need to cut mortises of ~3" deep and 4.25" wide in both the end piece and the end of the table. I would try about 5 of them. You should only use glue in the middle tenon. As for the remaining tenons, you can "pin" them. If you do through pins, arrange them decoratively. You can also pin from the bottom side, and cut short pins so that they pass through the breadboard and the tenon, but not all of the way through to the top. Because these are floating tenons, both sides of the joint will need to be pinned.The mitered piece is tougher. I'd try the floating tenon to join it to the table, and then use small bolts with capture nuts across the two mitered sections. Look at methods for joining a bed rail to a bed post to get an idea of how to go about this. Obviously, you'll be working on a smaller scale. Once again, just glue the middle of the floating tenon - no glue on the mitered sections.Keep in mind that wood takes some time to equilibrate: maximum width is usually in early summer, (I live in western WA, so I'm painfully aware of your weather conditions), as the humidity really doesn't drop out here until then. Wood will expand and contract more slowly after you get a finish on it, which is why you need to finish both sides of the table the same way (minus any rubbing out, which you can skip on the bottom side).Regardless of the finish you use, after it has dried up a bit, use a sharp utility knife and cut along the miter joint and the breadboard joint. The finish will eventually crack here anyways, so this makes sure the break is clean and where you want it.Good luck. Woodworking is mostly problem solving, anyways!-t

1. 
   Trezona | Feb 02, 2005 05:29am | #16

   Thanks for your suggestions. Would it be wise for me to wait for another several months (late summer) so that I have a maximum width change (decrease) on the main body of the table before I re-dimension the end pieces to fit. That way I will only have  an increase in width to deal with at my corner joints, i.e. gap formation at the junction with the corners during winter swelling.

2. 
   TTed | Feb 03, 2005 12:00am | #18

   You don't really need to wait. What you need, if you're worried, is a moisture meter. Maybe you can poke around and find someone that will lend you one for an afternoon. Buying one wouldn't be a bad idea, although I've always gotten by without one. A breadboard approach is going to have to accomodate both extremes, so you can just calculate what your gap is going to be (at the greatest, when the wood is driest) and then just estimate where you are in the annual cycle, and adjust accordingly. Because you're basically going to have to rely on mechanical joinery (vs. simply gluing) you'll have a little more lee-way with your tolerances. Basically, those miters will not be glued together, so you don't have to worry about breaking the glue line. I'd amend my original advice and say that you can glue all of the floating tenons into the mortises on the main slab. Then, you would ONLY glue the middle tenon to the breadboard end cap. The other tenons would then only need to be pinned on the cap piece. I'm probably not being too clear here, but a quick read through breadboard construction techniques should make things clearer. Good luck!

3. 
   Trezona | Feb 03, 2005 05:45am | #19

   Thanks to all of you. I will give it a go. Won't make that mistake again! I have the book "Understanding Wood" and will digest it completely.

4. 
   WillGeorge | Feb 02, 2005 06:28am | #17

   I was thinking..  May not be for you but I remember long ago a friend had sort of the same problem.. Really expensive slab..  Not sure it was 48" wide..... But pretty wide..

   He got a gun barrel boring bit (As I remember it needs a air compressor) and drilled through it, side to side, and used threaded rod, glue, and nuts.. Put some fancy wooden plugs in it to cover.

   I was not there so maybe he called a gun smith and had him do it.. I'd ask him but passed on....