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warped / bowed table top fix

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Forum topic by wrxg33k posted 03-27-2012 08:51 PM 12637 views 0 times favorited 18 replies Add to Favorites Watch
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wrxg33k

5 posts in 998 days


03-27-2012 08:51 PM

Topic tags/keywords: bowed twisted warped table top lowes creative ideas

I’m fairly new to “fine” woodworking and undertook a project of building a table from a Lowes Creative Ideas magazine – http://www.lowescreativeideas.com/idea-library/projects/DIY_Dining_Set_0911.aspx

I have the table built and but the top has twisted so bad that the table rocked. So I trimmed the legs to level it after some reading online but the top has continued to twist. I installed table leveling feet before I could see how bad the top actually is.

Does anyone have a suggestion as to how to fix this? I put 3 coats of poly on the top and 1 on the bottom of the wood slats.

Every time I look at the table sitting in our kitchen I’m so disgusted and am wishing we would have just bought one, but we’ve spent the money and the finish of the table is nice – it’s just so twisted and visible. Any help is appreciated.


18 replies so far

View DS's profile

DS

2132 posts in 1167 days


#1 posted 03-27-2012 10:39 PM

The fix is letting the lumber dry out a few weeks before milling or finishing. Be sure to store it flat and straight in a way that limits movement. I usually stack it on top of my storage cabinets and bundle it with cord. You can even straighten crooked wood this way.

When moisture exits wood, wood moves.

Not sure what to do with a finished table that is still drying out… Keep shimming I guess.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View Dusty56's profile

Dusty56

11684 posts in 2434 days


#2 posted 03-27-2012 11:52 PM

I agree that acclimation is key .
Also , you need to apply the same number of coats of finish on all sides of the table to equalize moisture gain / loss. How wide were the boards that you glued up to make the top ? Never mind , I saw the link now. 2×10 framing has so much moisture in it depending on where it has been stored. I also like how they offered this tip at the very end of the article.
GOOD TO KNOW:

Let your lumber acclimate to your work space for one week prior to machining. The material will stabilize, and the boards will be less likely to twist when you cut the individual parts from the larger pieces.


I also saw that they have the top fastened down with countless pocket screws and not allowing for any natural movement of the boards. Can you determine which board(s) are twisted enough to lift the leg(s) off the floor ? Can you remove the screws that are holding the top in place and just let it readjust to its new home ?

-- I'm absolutely positive that I couldn't be more uncertain!

View DS's profile

DS

2132 posts in 1167 days


#3 posted 03-27-2012 11:58 PM

You should also be aware that construction grade lumber is cut crooked and dried straight.

If you lay a 2X4 on the ground for a day, it will likely take on some very strange geometry by the next day.

Lumber mills discovered they get a better yield to let the computer analyze a log and cut the boards to match the shape of the log (crooked), then dry them straight. If you don’t fix it in place after removing it from the pile, it won’t stay put.

Problem is that any moisture change after it gets to your house, it will tend to go back to the crooked way it was cut.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View ELCfinefurniture's profile

ELCfinefurniture

112 posts in 1066 days


#4 posted 03-28-2012 01:33 AM

The wood might have been worked too soon.
Its proper practice to bring the wood into your shop and let it aclimate. Like hardwood flooring installers would with there material. Let it sit in the home for awhile before installing.
Also when you mill it for the first time, mill it roughly flat and square about a 1/4 to an 1/8 over in thickness, let it sit stickered up and then mill it again to final thickness. also, I would put even coats of finish on both sides to help moisture penetrate the top evenly.

-- {Current North Bennet street school student}

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wrxg33k

5 posts in 998 days


#5 posted 03-28-2012 02:38 AM

These seem to be great tips prior to starting the project. I also let the wood acclimate inside the house for almost a month. So that being said and the fact that the table is complete, what should my course of action be to correct the warping?

I’ve read about cutting the top slats down more and even leaving them outside under plastic sheeting?

View stevenmadden's profile

stevenmadden

174 posts in 1836 days


#6 posted 03-28-2012 03:18 AM

wrxg33k: I am no expert, and only took a quick look at the plans/description, but it seems to me that the problem is being caused by wood movement. It looks like the plan called for the top to be secured front to back and side to side (using some sort of pocket hole screw method), which does not allow the wood to expand and contract. Even if you let the wood acclimate properly and the wood is finished (sealed), it will still move over time. Cherry, for example, will shrink (contract) 1/8” per 12” of width (across the grain) going from a wet season to a dry season, and visa versa. If you have not accounted for this movement, then bad things happen. Again, I am no expert and didn’t study the plans too hard.

The only way that I can think to correct this problem is to undo the joinery of the top to the base, re-flatten the top (use a jointer plane, or an equivalent technique), and then reassemble the top to the bottom using a different technique (such as figure 8 fasteners), which will allow the top to expand and contract.

I have a friend who built a table out of solid maple. The top was 36” wide (or so) with bread board ends. He said the top moved 1/4” (cross grain) from season to season. If he had not accommodated for that movement, then I can picture his table doing the same thing yours is doing.

I hope this helps. Good luck.

Steven

View ~Julie~'s profile

~Julie~

578 posts in 1781 days


#7 posted 03-28-2012 12:33 PM

The problem isn’t you, it’s the plans.

I get infuriated at all the plans out there that are quick and make woodworking look cheap and easy. Everything is put together with construction lumber, screws and pocket holes. Sure it looks nice when it’s finished… but… what about later?

I see all types of decorating blogs where people are making tables just like you did, with the top screwed down to the aprons. Wood moves unless you can keep your furniture in an area with the same humidity all year long. Plus construction lumber is not dried to the proper level for indoor furniture.
Do as Steven said, unscrew the top and assemble it so that it can move.

P.S. Apologies for the rant

-- ~Julie~ followyourheartwoodworking.blogspot.ca

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wrxg33k

5 posts in 998 days


#8 posted 03-28-2012 12:43 PM

Ok so remove the pocket screws and get some figure eights. How do I fix the twisting of the wood that has already occurred? Is my only option a plane?

Thanks for everyone’s help. This is frustrating as you can imagine.

View chrisstef's profile

chrisstef

11457 posts in 1753 days


#9 posted 03-28-2012 12:44 PM

Along with everyones suggestions here, i think your sourse of action is to remove the table top from the pocket hole joinery and let it do whatever its going to do for a few days maybe a week. Then you’re going to need to figure out how to flatten it again. A big monster router planing sled or hand planes and winding sticks will work. From there i would eliminate the use of pocket screws and go with some figure 8 clips they use for attaching countertops. These will allow the table top to move seasonally without cupping / bowing. Another move would be to rip down your joint lines and replane them with planer if you have the access. Its totally salvagable but unfortunately its going to take some time and effort.

Good luck and welcome to the gang.

-- "there aren’t many hand tools as awe-inspiring as the #8 jointer. I mean, it just reeks of cast iron heft and hubris" - Smitty

View ~Julie~'s profile

~Julie~

578 posts in 1781 days


#10 posted 03-28-2012 01:12 PM

Is it possible to make a new top with proper wood?
this is what I use to attach table tops: http://www.leevalley.com/en/hardware/page.aspx?c=&p=40146&cat=3,41306,41309

-- ~Julie~ followyourheartwoodworking.blogspot.ca

View stevenmadden's profile

stevenmadden

174 posts in 1836 days


#11 posted 03-28-2012 04:31 PM

wrxg33k: A plane is not your only option, although it may be the best option. If you have never used a jointer plane before (or any planes for that matter), then I would not recommend running out and buying one for this project. Hand planes have a steep learning curve and there is a lot more involved in their use, care, and maintenance than meets the eye (or at least my eye before I took the plunge). Anyway, here are some alternatives off the top of my head (keep in mind, I don’t know what your tool set or skill set are), and they all require that you build some sort of shop appliance (most people refer to them as “jigs”).

The planer sled (you need a planer). I use mine as you will see it used in the video, to flatten long, rough, 8/4 stock. Works great. Here is the video from FineWoodworking:

http://www.finewoodworking.com/SkillsAndTechniques/SkillsAndTechniquesArticle.aspx?id=5245

Here is the companion article if you decide to build it (membership required):

http://www.finewoodworking.com/SkillsAndTechniques/SkillsAndTechniquesPDF.aspx?id=24118

If you decide to go this rout, I can send you the plans (PDF). Once you have one face of each board flat, use that face as your reference and run all the boards through (flat face down) until you have a uniform thickness throughout all the boards. I would then recommend gluing them together (it looked like the plans called for them to be installed separately). I would also consider using bread board ends to help keep things flat and in line, although this requires more skill and is not absolutely necessary.

Another method would be to build a router sled (you need a router), usually used to flatten slabs, but could easily be adapted to meet your needs. Here are a few article/videos that will give you an idea of what I am talking about:

http://www.finewoodworking.com/Workshop/WorkshopArticle.aspx?id=34350

http://www.finewoodworking.com/SkillsAndTechniques/SkillsAndTechniquesArticle.aspx?id=34272

http://www.finewoodworking.com/item/45658/offermans-slab-flattening-jig

http://www.finewoodworking.com/SkillsAndTechniques/SkillsAndTechniquesPDF.aspx?id=34293 (membership required)

If you do use a hand plane(s), there are as many ways to tackle this problem as there are people who tackle this problem. Here is my way; first, I start with a flat surface (workbench, etc.), and choose the side I want to flatten (referred to as the datum surface), then shim the opposite side that is referencing on the flat surface so the board doesn’t bend, rock or twist while I am working it (for shims, I use pine shims for big gaps and blue tape for small gaps). I use a #7 or #8 to do the work, the #7 (mine has a 55 degree high angle frog) for working difficult woods with switch back or some sort of figure or gnarly grain structure, the #8 (with the typical 45 degree standard angle frog) for the easy stuff. I keep an eye on any twist, bow, or cup as I am working. If you’re not careful, you can put twist in a board that was not there before or turn a board into a banana shape. I use winding sticks (I have heard them referred to as “truth sticks”) to check for wind or twist, and the sole of my plane to check for bow or cup. I choose my datum surface and work that side flat, regardless of whether it is cupped or bowed (there are different techniques used for removing cups as opposed to bows, some people prefer starting with the cupped side). Once I have my datum surface flat (and I mean flat, because all other surfaces will be referenced from this surface), then I joint one edge square to my datum surface (I use the same plane I used to flatten the face, some people use a power jointer, referencing the flat face against the fence). I then rip the opposite edge parallel using my table saw, and finally use my thickness planer to bring the opposite face parallel to my datum surface (in this case, the original face that I flattened) and to achieve my final desired thickness. The last step would be to cut to length (although, in your case they are already cut to length).

I know this was a long winded post, and if you have read through to this point, then you must really be determined to fix this project. I am willing to help in any way I can and wish you luck, whatever you decide to do. Keep us posted.

Steven

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reggiek

2240 posts in 2016 days


#12 posted 03-28-2012 04:40 PM

Other then replacing the top….there was an article in Fine Woodworking by the guy that is in one of the TV Sitcoms. He also makes Nakashima tables from slabs. His gig is excellent though and uses a router to plane wood flat….that is indeed an option here. Otherwise, you could remove the top and run it through a jointer to get a flat side and then plane it – or use two sided tape and tape it to a piece of flat wood and run through the planer until that side is flat. Wood conditioning – allowing wood to acclimate to your shop/area – is vital to reduce these kinds of problems….I would recommend you get a cheap moisture meter also and check the wood to insure it is at a workable state (around 12% or less).

-- Woodworking.....My small slice of heaven!

View DS's profile

DS

2132 posts in 1167 days


#13 posted 03-28-2012 11:13 PM

+1 on the clips Julie linked to. These are easy to use and allow the top to move without creating problems.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

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a1Jim

112858 posts in 2323 days


#14 posted 03-28-2012 11:31 PM

I agree with removing the top and pocket screws and replacing them with the clips or figure 8s I think I would replace the top wood with some kiln dry wood. I also agree the plans were far from correct as far as the top goes.

-- http://artisticwoodstudio.com Custom furniture

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wrxg33k

5 posts in 998 days


#15 posted 03-29-2012 12:59 PM

I will definitely be removing the pocket screws and installing figure 8’s.

In an attempt to salvage the existing top, what about cutting some relief cuts lengthwise in the top slats, then attaching several cleats to them, then attach the entire top to the base? This is the similar construction to a table my parents just purchased at a large furniture store like oak express.

My dad who is a carpenter, but not fine wood worker, suggested even going as far as steel angle bracket cleats but then that would not allow for any movement.

Thoughts?

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