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Table Top Mistake/Wood Movement12/20
In a recent project I made a poor choice of wood placement by gluing two pieces of wood perpendicular to the rest of the table. I now realize the error of my ways. The wood in this case is (mostly) quarter-sawed American Sycamore. I cut it and dried it myself for a year and then stored it on site to acclimate the wood to its environment for most of the fall while I worked on it. It is 7/4 thick. The perpendicular piece is 11" long so there is 11" of wood that will want to move and won't be able to. It is glued and doweled so I don't think it's going anywhere until it cracks (if it does.) By using temperature and relative humidity I estimate that the wood fluctuates between 9 & 10% moisture content during the current winter season (southeastern, PA). If I have to I am willing to make a cut down the middle of the two poorly placed pieces to release pressure but don't want to if it isn't necessary. I included a picture to provide as much information as possible. I will be gluing and doweling the table top to solid wood legs/supports. Is 11" a small enough piece to survive or will it bust the table over time?
12/20
I don't think a year of air drying is near enough to stablize 7/4 anything.
As a rule of thumb an inch per year of thickness for air dried and that should be indoors. It is near impossible to get air dried wood down to 9-10 %. I am in norheast pa. and weather here varies little from where you are. Perhaps Dr Gene will pipe in. regards Harry DeVrieze 12/21
Doweled or not, that top is not going to last. It might not fall into pieces, but cracks will open and there's no relief cutting you can do to prevent this. You might simply cut the ends of the top, with the ill-conceived pieces, completely off and satisfy yourself with a smaller table. Also, as Harry has already said -- doweling and gluing the legs to the top is a bad idea if the leg assembly is going to include a skirt or stretchers perpendicular to the length of the top. Doing so will only wreak more havoc. 12/21
I agree with Andrew and Harry. The top is a built-in failure waiting to happen. I think that you are in repair mode. I see two approaches: 1) Rout out the cross-pieces & replace them, or 2) Make 2 rip cuts along the glue joints that abut the end pieces, knock out those pieces and replace. Regards 12/21
Andrew, please let me recommend a book for you. IMHO it's a must read for anyone taking woodworking as seriously as you obviously are. In my opinion, this wood movement issue is the least understood but perhaps the most important principal in woodworking. Most of us learned this the hard way. Welcome to our world. Hoadley - Understanding Wood
At least you know you did something wrong;) I also think a copy of Hoadly would be some valuable reading for you.
I also agree your wood hasn't dried long enough, but since you are this far, here is what I'd advise. I hope this is a personal piece and not a paying job. Use it as a learning experience and watch what happens to your top if you leave it alone.
Or, crosscut off the entire width of those two pieces. Then you can attach full width breadboard ends the right way.
We've all done stuff wrong, just make sure you learn from it.
Jason
there is no fix possible.i suggest you enjoy its beauty till it fails.and learn like we all did.speaking from experience
I appreciate everyone chiming in with their experience. It looks like this one won't survive as it is. It is a personal project so I have some leeway in addressing the problem.
First, it looks like I didn't let it dry long enough. It's been about 15 months now since I cut the original log but should have let the thick wood go longer. I have other wood now that is drying that I will let dry longer.
As far as the table goes I like the breadboard option and am going cut off the end and reattach it using the breadboard technique. The table doesn't have a skirt and the legs (I included a picture below) are the same width as the table with the grain moving in the same direction. As far as my understanding goes this should move at the same rate as the table and in the same direction so it should be okay to dowel and glue? There is more face grain in the legs though than in the mostly quarter-sawed top.
I will buy the Hoadley - Understanding Wood book. Thank you for the suggestion. I enjoy learning about new things and it looks like this book contains quite a bit of information.
If anyone notices something else that I did wrong feel free to post and tell me. Thanks again for everyone's input and suggestions. This helped me make an informed decision.
Hi Andrew
Jason,
That does make sense. In my original design the legs were going to sit at the end but now I realize that I can't do that anymore. I don't particularly like the aesthetics of the overhanging breadboard. I have given the whole thing a little more thought and I think I will just cut the ends off and attach the remaining portion to the legs with a few copper brackets with slots allowing for the horizontal wood movement.
In addition to the brackets, I am considering a double rabbet joint without any glue. Since the legs use more face-cut wood than the quarter-sawed table top I want to allow for any difference in movement that could occur. Also, this may help if the wood is not completely dry as it was asserted in the beginning.
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