Blanket Chest Lid warped lengthwise.

[Sam Dotson]

I just finished (I thought) m y first Blanket Chest, and as I was finishing up attaching the lid via torsion hinges, I discovered the lid is warped lengthwise. I considered mortising the hinges, but since one end of the lid is already touching the chest, I don’t think this will resolve the issue. I also considered adding cleats across the grain, but I don’t see how this solves the problem either. I would appreciate your recommendations on how I should resolve this.269671269678269675269673
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[Joe Hillmann]

What I would try is to put a shim on the side that is touching and put some weight on the other side, let it sit for anywhere from a few hours to a few months and see what happens.

[Howard Acheson]

Leave the top open to allow air to get to both sides. If you have had the top lying in a position that restricted air to only one side, new, equalized wood will warp like that. Leaving the top open for a week or two will generally allow the wood to become flat again.

[Kevin Bourque]

Some friction catches on the corners will help some.

[Ralph Boumenot]

Did you check to ensure that the base cabinet isn't twisted? It may be the photo is warped, but the first picture (back with hinges) looks like the ends slope downward a bit.

[Myk Rian]

I had a box lid do that. After making a new lid, it straighten itself. Took a couple days.

[Todd Burch]

Pictures 2 and 4 hint at a spike knot in the middle of the front board.

If the warping is due to uneven moisture exposure, it should flatten out. If it doesn't, oppositely curved cleats screwed underneath should fix it.

Todd

[Roy Harding]

The others have all made good and valid suggestions, try them out.

I make a LOT of chests. Whenever possible (when it's aesthetically appropriate), I make the lids with bread board ends - it helps prevent the twisting of the panel. When that isn't possible, I use cleats screwed to the bottom of the lid - for the same reason.

Nice looking chest, by the way.

[Sam Dotson]

Ralph, I just went out to the shop and remeasured and the cabinet is square.

[Sam Dotson]

Todd, please tell me more about the spike knot issue. What is the best way to estimate the amount of curve in the cleat? I'm assuming the convex cleat goes on the high side end, and the concave cleat goes on the low side end, right?

Sam

[Jim Matthews]

I'm late to this party, but contemplating similar projects.

Since no one else has mentioned it, allow me to express my admiration for your work.
It's a handsome piece, and shows really attention to detail - particularly in grain choices.

Has there been a big swing in Humidity between the assembly day and when the warp appeared?
(I'm in agreement that it might be best to leave things alone for a week and see what happens.)

*****

Am I to understand that you might put mechanical cleats horizontally across the board to tame the warp?
I would think that would only be as strong as the fasteners used. This kind of deflection is powerful enough to break glue bonds -
a couple of screws won't stand a chance, countering all that force in a small area.

I would think routing a sliding dovetail dado would make for a stronger fixture (as in making shelves in a bookcase).
I would make the long battens to fit in a housed sliding dovetail (http://tonykonovaloff.com/?page_id=57), rather than full length. Those could be quite deep,
even through to the top surface where they could be wedged in place. I think they could be pressure fit and thereby removable.
(Scroll down to the bottom of Tony Konovaloff's page to see an example.)

That way, you could remove it if the attempt failed and the batten breaks.

While it's radical surgery, if the entire panel doesn't stabilize on it's own, have you considered retrofitting it as three floating fielded panels, like a door laid flat?
While it would break up the clean line of the piece, it might cut the amount of force generated by warping, dividing it along four rails.
(If you made it into three panels, that is.)

[Todd Burch]

Hi Sam.

A spike knot is a knot that starts at the edge of a board and travels inward towards the pith of the board. Thin boards such as these are very prone to warping at a spike knot. See this link at the SPIB (Southern Pine Inspection Bureau): http://www.spib.org/glossary.shtml#s. In this glossary, search all occurrences of SPIKE and then search all WARP. Your glued up board has TWIST, a form of WARP.

Here's a drawing that represents the idea of my suggestion.

269721

The bottom image is a flat top with cleats. I drew the top 36" long, 18" wide and 3/4" thick. It has two cleats, 32" long, 1.25" tall and 3/4" thick, placed 3" in from each side and centered end-to-end. I drew a 1/2" wide bevel on the ends for looks.

The uppered bowed image is the same lid, but with a 3/8" bow in it (or, 3/16" per end). For the cleat, I show them 1.25" tall at each end, and 1/8" taller in the middle.

In theory, if the bottom cleat was rigid enough, its top edge would not need to be convex. In practice, I would actually start with a flat cleat (not convex) and see how much of the twist I could pull down.

If a flat cleat did not get enough of the twist out, I would then start shaving the cleat's top edge down, starting somewhere towards the middle or left 1/3 of the cleat, and working towards the left end, since the left end of your top is twisted up, a bit at a time. In this case, the case of the cleat not being rigid enough to pull the top flat, then the alternate objective is to pull the top and the cleat together, (two convex surfaces), until they counteract each other and become flat when screwed together.

I hope this helps.

Todd

[glenn bradley]

First off, beautiful chest. The figure is just bold enough to be really interesting without being so wild as to overpower. Nice coloring too.


I had a box lid do that. After making a new lid, it straighten itself. Took a couple days.


If the warping is due to uneven moisture exposure, it should flatten out. If it doesn't, oppositely curved cleats screwed underneath should fix it.

I am also in this camp. If you can wait it out, I would wait awhile and see if it returns to flat on its own. If not, a cleat running left to right a few inches back from the front edge should do it. Use carefully placed screws so that you can remove and replace the cleat. I would start with a lightly bowed cleat (bowed side to the lid) as you are trying to pull enough past flat so that the tension will return it to flat. You can use a plane to lessen the bow as you test the fit till you get what you want. You could also start flat and go the other way; whatever suits your fancy.

[johnny means]

I would route a series of relief cuts across the bottom of the lid, v-grooves, maybe half way through. This would probably release most of the stress. Then I would pull the panel into compliance with a couple of battens .

[eugene thomas]

I would wait out and see what happens or go to wood pile and find wood to make new top. The chest looks real top notch though.

[Sam Dotson]

Todd, thank you so much for taking the time to show this in a drawing. I completely understand now about the cleats and the spike knot issue. The spike know issue is a big lesson learned for me and helps to explain my situation. I expected to have warping across the width because I intentionally didn't alternate the grain to get a better face grain and color match, but I didn't expect the warp lengthwise. Thanks again!

[Sam Dotson]

Jim, thank you for the nice compliment on my chest. I think I will leave it for a week or two to see what happens, and in the meantime, I may start to glue up another top that could be used as a replacement, or for the next chest if this lid corrects itself.

[Jim Matthews]

Please keep us posted, I'm having the same sort of movement problems in my basement shop.

(It's a bit more damp, along the Taxachusetts coast than most of my furniture seems to like.
I've still got two drawers stuck in my latest cabinet.)

[Wade Lippman]

What I would try is to put a shim on the side that is touching and put some weight on the other side, let it sit for anywhere from a few hours to a few months and see what happens.

I had a warped 7' piece of walnut; about 6" wide. I clamped it to a steel beam with reverse curve for a year; even steamed moisture in. When I took the clamps off it went back to how it was before.

Good luck getting anything to unwarp.

[Chris Hachet]

Nice looking chest....

[Zach Callum]

Seriously, don't worry about it. Does it really detract from the piece? I don't think so. It really isn't that bad.