How much warp is too much?


Tbone

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Just like the other recent poster, I also am fairly new, at least to furniture making. I too have a couple of bowed pieces, though I haven't tried to edge glue them... Yet. But I have 5 boards that will make up a table top.

I have quarter sawn oak that is 4 1/2 wide x 46 and a couple of boards have a cup with a gap of about 1/4" at the worst. The wood is still 7/8" thick so I have a little help in that I need to plane them down to 3/4.

The table top that these will make up will have breadboard ends and I'm considering using dowel joints to aid in the edge gluing. I'm just afraid that even with these helps of planing and dowels and breadboard ends, I'll still have trouble.

Thoughts?

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You'll need to both joint and plane the stock to flatten. A 1/4" cup seems excessive. Roughly speaking, you may loose up to 1/2" of thickness by the time you joint one side, then plane the other to make flat. May be able to rip the bowed pieces in half, edge joint and re glue to remove most of the problem before jointing and planing.

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Great response, thanks! I bought these at a hardwoods store in Seattle where the wood was stored standing up. That can't be good. When I got them home, I stored the in my shop for a week or three laying flat on top each other. Not sure if that contributed to the change but doesn't seem like it should have...

As for advice: i only have a planer. I can take to a friend with a jointer but why are both needed? Is it because the planer just tends to follow the shape of the board (squeezing it between the roller and table) and the jointer is only getting the high spots? I'm assuming so.

Sounds like overall, the amount of warping is too much for glue +dowels plus breadboard ends?

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My guess is that you'll be able to straighten them out and still maintain 3/4".  Worst case you may have to flip / flop curvature on glue-up to help balance a 1/16" or so, but it should be fine (especially with BB ends).  When everything is ready for finishing make sure to coat all sides to maintain even seasonal change in the wood..

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Follow up: I told you I was a newbie! As I began to make the sled described, I pulled out some mdf for making the sled with and set it on my bench. It also appeared to not be flat! Ok, hold on.....that's fishy. I have a long 42" level so I took it out, layed it on top the bench itself and discovered my bench was crowned in the middle!!! When I layed my oak lumber on top the mdf, I saw that the actual warpage was pretty minimal for most of the boards. Geez! My bench was not flat.

Regardless, there is still some boards that need the attention that the sled could provide so I still plan on making it the sled-jig. Notice the video shows 2 pieces of plywood to make the sled for rigidity. I have 3/4 mdf so it's already going to be heavy. Opinions on how necessary it is to make the sled with 2 pieces?

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Wood can develop a bow by storing standing up. Try standing the board with the back of the bow facing out till your ready to work the board. You can try spraying water on the cupped side to see if the board will relax. If the board wont relax chances are it's stress in the wood, then use the planer method above. 

 

-Ace-

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